study of micro-blowing technique · a study of micro-blowing technique ... 3.1 wake traverse ......

A Study of Micro-Blowing Technique

Nam Suk Choi

A thesis submitted in conformity with the requirements for the degree of Master of Applied Science

Graduate Department of Institute for Aerospace Studies University of Toronto

Copyright @ 1999 by Nam Suk Choi

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Abstract

A Study of Micro-Blowing Technique

Nam Suk Choi Master of Applied Science

Graduate Department of Institute for Aerospace Studies University of Toronto

1999

A skin fiction reduction method called the Micro-blowing Technique was used to study

the reduction of profile drag on a symmetrical airfoil. A twedimensional symmetrical

airfoil, the UTIAS-MBT model, was designed and built a t UTIAS to verify the reduction

of the profile drag. The momentum deficit method, more commonly known as the wake

traverse, was utilized to measure the profile drag of the model at zero angle of attack.

When air was blown through the micro voids of the porous plate, the drag of the mode1

was effectively reduced. Maximum profile drag reduction of approximately 6% was ob-

served wit h the current blowing system. h r t h e r studies of the Micr~blowing technique are needed to fully investigate the profile drag reduction.

Acknowledgement s

This project would have not been possible if it were not for the help of al1 the people who

love the art and science of flight. 1 would like to thank my supervisor, Dr. DeLaurier, for inspiring me to take on such a chdlmging project, and for his continuing support for many things that he has provided throughout a i s project.

1 would like to thank al1 the people at deHavilland Inc., now Bombardier Toronto,

who made this project a possibility. Especially, 1 would like to thank Brian Eggleston for allowing this project to be a deHavilland-supported project. Thanks to Dr. Ian Fej tek for his continuing support and guidance throughout the project; Jeff Petzke for his efforts

to make this project a possibility; John b e y for his help in ordering the porous plate;

and Dave Lye for lending his computer and a data acquisition card. My sincere thanks go to Dr. Hwang at NASA Lewis. He has provided al1 his pa-

pers and information on his tests on Micreblowing Technique and has also provided an

enlightening visit to the facilities at NASA Lewis.

Lastly, 1 would like to thank my family and friends for their continuing support and

encouragement. Thanks to Anne Lim, Scot Rutherford, Mark Yun, Ji-Yeon Lee, and Simon Park for reading through my drafts. A special thank-you goes to al1 my sisters

and brothers for putting up with their little brother and taking care of me for many

years. 1 thank my parents for their great life lessons. Most of d l , 1 would like to give

my full hearted thanks to my brother, Nam-Joo, for supporting me for last fourteen long

years!

iii

Contents

List of Figures vi

List of Tables viii

List of Symbols x

1 Introduction 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Background 1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Project Definition 2

The Model 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Profile 3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Design of the Mode1 5 . . . . . . . . . . . . . . . . . . . . . . 2.2.1 Mode1 Profile Development 5

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.2 Porous Plate 9

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.3 Plenum 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.4 Mode1 Span 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Mode1 Construction 10

. . . . . . . . . . . . . 2.3.1 The Leading-Edge and The Trailing-Edge 11 . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.2 Main-BodySection 13

. . . . . . . . . . . . . . . . . . . . . . . 2.3.3 Plenum for Porous Plate 13 . . . . . . . . . . . . . . . . . . 2.3.4 Final Assembly and Final Finish 14

3 Experiment and Analysis 19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Wake Traverse 19

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Pressure Measurements 23 . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.1 Dynamic Pressure 23

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.2 Static Pressure 26

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.3 Total Pressure 28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.4 Blowing Speed 28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3 Position Measurements 29

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4 Micro-blowing 29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5 Data Acquisition 32

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6 Run Grid 32 . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.7 Wake Thverse Procedure 35

4 Results and Discussions 37 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Baseline Drag 39

. . . . . . . . . . . . . . . . . . 4.2 Traverses with Outer Porous Plate Only 39 . . . . . . . . . . . . 4.3 naverses with Porous Plate and HDPE Inner Plate 39

. . . . . . . . . . . . . . . . . . . . . . . . . 4.4 Summary of Measured Drags 45 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 Error Analysis 46

5 Conclusions 54

6 Future Reconimendations 56

References 57

A Data Tables 58 . . . . . . . . . . . . . . . . . . . . A . 1 Solid Plate Traverses: Baseline Drag 58

. . . . . . . . . . . . . . . . . . . . . . . . . . . . A.2 Porous Plate Traverses 67 . . . . . . . . . . . . . . . . . . A.3 Porous Plate with HDPE Inner Plate On 82

B Profile generation program: Efoi1.c

C Porous Plate Calculation Proqam: Porp1ate.c

D Data Acquisition Program: Fourchs.bas

List of Figures

2.1 An Isometric Drawing of the UTIAS-MBT Mode1 . . . . . . . . . . . . . 4

2.2 Profile of the UTIAS-MBT Mode1 . . . . . . . . . . . . . . . . . . . . . . 6

2.3 The Final Mode1 Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.4 Inviscid MSES Result for the Final Mode1 Profile . . . . . . . . . . . . . 8

2.5 Drawing of the Porous Plate Selected . . . . . . . . . . . . . . . . . . . . 15

2.6 Drawing of the Plenum Box . . . . . . . . . . . . . . . . . . . . . . . . . 16

2.7 Picture of a Successful LE Styrofoarn Core . . . . . . . . . . . . . . . . . 16 . . . . 2.8 Picture of the LE Component After the Application of Fiberglass 17

. . . . . . . . . . . . . . . . . . 2.9 Picture of the Main-Body Section Rame 17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.10 Picture of the Plenum 17

2.11 Picture of the Completed Mode1 . . . . . . . . . . . . . . . . . . . . . . . 18

3.1 UTIAS Aeroscoustics ?iinnel Facility . . . . . . . . . . . . . . . . . . . . 20

3.2 UTIAS Aeroscoustics mnnel Test Section Drawing . . . . . . . . . . . . 21

3.3 Calibration of MPX5010DP Pressure Tkansducer . . . . . . . . . . . . . 25

3.4 Calibration of MPX2100AP Absolute Pressure Tkansducer . . . . . . . . 27

3.5 MPX4115A Transfer h c t i o n (from Motorola Technical Data Sheets) . . 28

3.6 Blower Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

3.7 Calibration Graph of the Honeywell 164PC Low Pressure Sensor . . . . . 31 3.8 Picture of the Tkaversing Arm with a Ruler for Position Measurements . 33

3.9 Picture of the lkaversing Arm in the Wake of the Model (Zero Position) 35

. . . . . . . . . . . . . 4.1 Integrand Profile of Solid Plate Traverses 1 and 2 40

4.2 Integrand Profile of Solid Plate 'Praverses 3 and 4 . . . . . . . . . . . . . 41

4.3 Integrand Profile for Al1 Solid Plate Cases . . . . . . . . . . . . . . . . . 42

4.4 Integrand Profile of Porous Plate without HDPE Inner Plate Cases: PO4WPLUG and P04WNPLUG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

4.5 Integrand Profile of Porous Plate without HDPE Inner Plate Cases: P04BS05 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . and P04BS08 44

4.6 Integrand Profile of Porous Plate without HDPE Inner Plate Case: P04BS10 44

4.7 Integrand Profile of Porous Plate with HDPE Inner Plate Case: WIO4PLUG 46

4.8 Integrand Profile of Porous Plate with HDPE Inner Plate Cases: WI04BS00 and WI04BS05 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

4.9 Integrand Profile of Porous Plate with HDPE Inner Plate Cases: WI04BS08 and WI04BS10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

4.10 Integrand Profile of Porous Plate with HDPE Inner Plate Cases: WI04BS13

and WI04BSl.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

4.11 Profile Drag Variation witb the Blowing Parameter . . . . . . . . . . . . 50

4.12 Cd/Cdbo>r Vanation with the Blowing Parameter . . . . . . . . . . . . . . 51 4.13 CdwakeVariationwiththeBlowingParameter . . . . . . . . . . . . . . . 52

. . . . . . . . . . . . . . 4.14 CctblWing Variation with the Blowing Parameter 53

vii

List of Tables

2.1 A Summary of Porous Plate Data . . . . . . . . . . . . . . . . . . . . . .

3.1 Channel Assignments on RTI-800 . . . . . . . . . . . . . . . . . . . . . . 3.2 Run Grid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A. 1 BDSOLIDl: Solid Plate Traverse 1 Run Data . . . . . . . . . . . . . . . A.2 BDSOLIDl: Solid Plate naverse 1 Integrand Summary . . . . . . . . . . A.3 BDSOLID2: Solid Plate Traverse 2 Run Data . . . . . . . . . . . . . . . A.4 BDSOLID2: Solid Plate Traverse 2 Integrand Summary . . . . . . . . . . A.5 BDSOLID3: Solid Plate Traverse 3 Run Data . . . . . . . . . . . . . . . A.6 BDSOLID3: Solid Plate naverse 3 Integrand Summary . . . . . . . . . . A.7 BDSOLID4: Solid Plate Traverse 4 Run Data . . . . . . . . . . . . . . . A.8 BDSOLID4: Solid Plate naverse 4 Integrand Summary . . . . . . . . . . A.9 PO4WPLUG: Run Data of Porous Plate naverse with Plugged Pipe . . . A.10 P04WPLUG: Integrand of Porous Plate Traverse with Plugged Pipe . . . A. 11 P04WUNPLUG: Run Data of Porous Plate Traverse with Unplugged Pipe

A. 12 P04WUNPLUG: Integrand of Porous Plate Tkaverse with Unplugged Pipe A. 13 P04WUNPLUG: Massflow of Porous Plate 'Ikaverse with Unplugged Pipe A.14 P04BS05: Run Data of Porous Plate Traverse with Blower Setting of 05 . A. 15 P04BS05: Integrand of Porous Plate naverse with Blower Setting of 05 . A.16 P04BS05: Massflow of Porous Plate Traverse with Blower Setting of 05 . A. 17 P04BS08: Run Data of Porous Plate Traverse with Blower Setting of 08 . A.18 P04BS08: Integrand of Porous Plate Traverse with Blower Setting of O8 . A.19 P04BS08: Massflow of Porous Plate Traverse with Blower Setting of 08 . A.20 P04BS10: Run Data of Porous Plate Traverse with Blower Setting of 10 . A.21 P04BS10: Integrand of Porous Plate Traverse with Blower Setting of 10 . A.22 P04BS10: Massflow of Porous Plate Tkaverse with Blower Setting of 10 . A.23 WI04PLUG: Run Data of Porous Plate Traverse with Plugged Pipe . . .

A.24 WI04PLUG: Integrand of Porous Plate naverse with Plugged Pipe . . . A.25 WI04BS00: Run Data of Porous Plate Traverse with Blower Setting of 00 A.26 WI04BS00: Integrand of Porous Plate Traverse with Blower Setting of 00 A.27 WI04BS00: Massflow of Porous Plate Traverse with Blower Setting of 00 A.28 WI04BS05: Run Data of Porous Plate Traverse with Blower Setting of 05 A.29 WI04BS05: Integrand of Porous Plate Traverse with Blower Setting of 05 A.30 WI04BS05: Massflow of Porous Plate lkaverse with Blower Setting of 05

A.31 WI04BS08: Run Data of Porous Plate lkaverse with Blower Setting of 08 A.32 WI04BS08: Integrand of Porous Plate Traverse with Blower Setting of 08

A.33 WI04BS08: Massflow of Porous Plate Traverse with Blower Setting of 08 A.34 WI04BS10: Run Data of Porous Plate 'Ikaverse with Blower Setting of 10 A.35 WI04BS10: Integrand of Porous Plate Traverse with Blower Setting of 10 A.36 WI04BS10: Massflow of Porous Plate Traverse with Blower Setting of 10

A.37 W04BS13: Run Data of Porous Plate Daverse with Blower Setting of 13 A.38 WI04BS13: Integrand of Porous Plate 'ikaverse with Blower Setting of 13

A.39 WI04BS13: Massflow of Porous Plate Traverse with Blower Setting of 13 A.40 WI04BS15: Run Data of Porous Plate Traverse with Blower Setting of 15

A.41 WI04BS15: Integrand of Porous Plate 'ikaverse with Blower Setting of 15

A.42 WI04BS15: Massflow of Porous Plate Traverse with Blower Setting of 15 A.43 Summary of Profile Drags . . . . . . . . . . . . . . . . . . . . . . . . . .

List of Symbols

exit area of the porous plate area of the pipe aspect ratio (T/D) porous plate span (width) mode1 chord length profile drag coefficient baseline drag coefficient

blowing component of the profile drag coefficient porous plate drag coefficient with plugged blowing system wake component of the profile drag coefficient acceleration due to gavity total pressure at wake station water column height (total head reading - static head reading) mass fiow rate of the blowing air

blowing parameter static pressure at wake station dynamic pressure blowing dynamic pressure st atic pressure static pressure found using water manometer readings total pressure total pressure = Q + P'J20 fkee stream static pressure free stream dynamic pressure Reynolds number dynamic pressure measured free stream velocity

ub blowing speed V air speed

supply voltage to the pressure tramducers Y traversing direction

Pa density of air Pb density of the blowing air

Pw density of water Y c nomalized y-distance (y-axis is the traversing axis)

Chapter 1

Introduction

A skin friction reduction technique called Micreblowing Technique (MBT)[l] was used to study the reduction of the profile drag of a two-dimensional symmetrical airfoil. This paper describes the model, the methodology used to measure the profile drag and the results obtained.

1.1 Background

Drag reduction has long been a challenge to aerodynamic researchers. Many different methods such as laminar flow control (LFC) technology through surface suction, natural laminar flow (NLF), riblet applications, and mass injection (blowing) were tested. These methods had several associated problems which restricted their use. Recently, a new way

of achieving drag reduction has been developed by NASA engineers. Hwang[l] at NASA Lewis developed an innovative skin-fiction reduction technique called Micro-blowing

Technique (MBT) .

Micreblowing is defined as the blowing of a small amount of air/water per-

pendicularly to the surface in question to control the gradient of the flow

velocity profile and to reduce the roughness of the skin, thereby reducing skin friction[Z].

Tests on flat plates proved a skin fiction reduction of up to 60%[3]. Such a large reduction in skin friction drag is phenomenal. A more usefid drag reduction would reduce the profile drag of a body as well. A study of MBT's effect on

required for further development of this interesthg technique. the total profile drag was

1.2 Project Definition

This study consisted of building a model and studying the profile drag characteristics. A Computational Fluid Dynamics (CFD) code called MSES[4] was used for preliminary studies on possible model profiles. The mode1 is a symmetrical "flat-foil" with a porous insert section on one side. The Micro-blowing was applied through this porous section. The profile drag was measured by the momentum deficit method, more commonly known as the wake traverse.

A linear traversing mechanism with 0.001 inch accuracy was utilized to step through the wake at approximately 9.5 cm behind the trailing edge of the model. A profile drag was calculated after each complete traverse. Profile drag results for Mnous blowing speeds at zero angle of attack were obtained and compared with the baseline drag values.

The following chapters describe the model design process and the building process, as well as the results obtained from the experimental investigations.

Chapter 2

The Mode1

The UTIAS-MBT model was designed and built at the University of Toronto Institute

for Aerospace Studies Low Speed Aerodynamics Lab. This chapter descnbes the devel-

opment of the UTIAS-MBT model and its construction in detail.

The UTIAS-MBT model is a symmetrical, two-dimensional, 6.4% thick airfoil. It consists of three main sections: the leading-edge section, the main-body section, and the

trailing-edge section. On one side of the main-body section, a 9 inch by 5 inch (22.86 cm

by 12.70 cm) aluminum plate is inserted. The central region of this aluminum plate is an

8 inch by 4 inch (20.32 cm by 10.16 cm) porous section through which the micro-blowing

is applied. Figure 2.1 shows an isometric drawing of the model.

2.1 Profile

The model profile consists of three distinctive sections as indicated in Figure 2.2. First,

the leading-edge is an elliptical leading-edge with semi-major axis dimension of 4.41

inches (1 1.20 cm) and minor-axis dimension of 1.25 inches (3.18 cm). The leading-edge section is followed by a flat main-body section, which is 9.5 inches long. This section has

a constant thickness of 1.25 inches (3.18 cm). Following the main-body section is the

sharp parabolic trailing-edge section. This parabolic trailing-edge section has zero slope,

coming off the main-body section, and has a trailing-edge angle of 12.7591 degrees. The trailing-edge section is 5.59 inches (0.1419 m) long and 1.25 inches (3.18 cm) thick. Total

chord length of the model is 19.5 inches (0.4953 m) with a maximum thickness of 1.25

inches (3.18 cm).

UTIAS-MBT M o d e l

H e l g h t : 24 ,4 in, C h o r d i 1 9 5 in. Thlckness: 1.25 i n ,

Figure 2.1: An Isometric Drawing of the UTIAS-MBT Model

2.2 DesignoftheModel

Designing the twedimensional symmetncal model required the determination of a model profile and its spanwise length. Once a model profile had been determined, a porous plate

was selected accordingly. This section briefly outlines the model profile development process and its span d e

t erminations.

2.2.1 Mode1 Profile Development

Development of the model profile was aiKected by many factors:

a Reynolds number requirement (RN 2 1,000,000)

a chord length

porous plate size

plenum requirement for micro-blowing application (thickness requirement)

streamwise tunnel test section length

a traversing a m location

a minimal or no pressure gradients over the flat section of the model

Al1 of the factors mentioned above were considered in designing the model but two factors were considered as the most important. These were the chord length and the pressure distribution over the model.

For example, the model had to have a sufficient chord length in order to have a Reynolds number of a t least one million. Yet, it was not feasible to have such a long main-body section due to the high cost of the porous plates. A bigger model needs a bigger porous plate and a bigger porous plate would cost much more due to the increased number of holes in the plate. However, at the same t h e , if the porous plate is too small

then no profile drag reduction would be obseved. Another factor which influenced the model profile was its maximum thickness. This

was an important factor because having a very thin mode1 meant that the blowing air had to be supplied in very thin tubes and this would not d o w enough m a s flow to achieve the amount of blowing needed. Having the model too thick waa a problem as

Figure 2.2: Profile of the UTIAS-MBT Mode1

well. A thick model would have a large pressure drag and would require a relatively long

leading-edge to alleviate the pressure spike and a long trailing-edge to prevent premature separation of air. This would make the entire model chord too long and interfere with the traversing mechanism.

Development of the profile for the UTIAS-MBT required usage of a CFD solver called MSES. Two cases were explored with MSES: inviscid and viscous. Pressure distributions and skin friction distributions were used to get an idea of the flow around a particuiar model profile. Initially, a profile was generated using a program called "Efoil.c"(see A p pendix B). This was a C-program, which generated three sectional curves in normalized

coordinates. Since the model was symmetrical, only one side of the profile was generated. The other side was easily copied by mirroring. Normalized x and y CO-ordinates of the newly created profile was used as an input to MSES. In MSES, an inviscid and a viscous case were explored. The resulting pressure distribution and the skin friction

coefficient distribution were examined to decide if the profile was appropriate. Initially, a profile with 10% thickness to chord ratio was generated with a relatively

short leading-edge and trailing-edge. The leading-edge was only 10% of the chord and the

trailing-edge was 15% of the chord length. After examining inviscid and viscous cases of

this profile at M= 0.2 & RN= 1.OE6, it was clear that this was not a good configuration.

On the next trial, a thinner version of the above profile was tested. This time it was only

6.5% thick. It still had similar characteristics to the previous profile; a pressure peak

at the leading edge and substantial pressure gradients over the flat main-body section.

After a few more trials, a profile with 24.5% leading-edge, 31.1% trading-edge and 44.4%

main-body section with 6.5% thickness to chord ratio, as in figure 2.3, was selected for the model profile. An inviscid case MSES run result for the final model profile, as in

figure 2.4, clearly indicated a minimum pressure coefficient (C,) of -0.25. This was only

a quarter of that for the 10% thick case with a shorter leading-edge. The final profile also had lower pressure gradients over the flat section (main-body) of the profile. Thus,

the fint of the two important requirements needed to determine the model profile, the

pressure distribution, was satisfied.

Once the nonnalized profile was selected, a chord length had to be determined. A tentative chord length of 18 inches (45.72 cm) was chosen at tMs time due to the Reynolds Number (RN) requirement. A RN of over one million was required at a moderate tunnel

speed (apprairnately 160 ft/s) . With this tunnel speed, RN was 1.6 million (1,653,644).

Thus, the second of the two important factors used to determine the model profile, the

chord length, was satisfied.

Figure 2.3: The Final Model Profile

ELLIPTICRL FLAT FOIL Mach = 0.197 Alfa = 0.000 CL - -0.0002 CD = 0.00000 CM = 0.0001 L/D - 0.00

Figure 2.4: Inviscid MSES Result for the Final Model Profile

A chord length of 18 inches resulted in a main-body section 8 inches long (44.4% of 18 inches), and this in turn allowed the porous region to be 8 inches long in chordwise direction.

Later, for the construction of the model, an extension of 1.5 inches of the main-body was required. This fortunately did not affect the RN requirement. RN only increaaes if the reference length (chord length) is increased. The porous plate required an extra one inch, a half-inch on both the front and the back end of the plate, for screws to fix the plate on the main-body frame (see Figure 2.5). An additional half-inch, a quarter of an inch at the leading-edge side and the other quarter of an inch at the trailing-edge side, was

utilized for the balsa strip which acted as an agent to hold the Styrofoam leading-edge and the trailing-edge to the aluminum main-body frame. This resulted in a final chord length of 19.5 inches (49.53 cm). The final resulting model profile, shown in Figure 2.2, was a 6.4% thick profile with the previous thickness remaining unaltered at 1.25 inches.

2.2.2 Porous Plate

As Hwang mentions in his report, the porous plate is the key factor in achieving effective micro-blowing 131. The plate used by Hwang was used as a basis for developing the porous plate for the UTIAS-MBT model. Similar hole arrangement, porosity, and aspect ratio (AR=T/D) were used because these gave the best skin fiction drag reduction as indicated in Hwang's report. An aspect ratio of greater than 4 was desired. Aspect ratios of 4 and 5 were investigated, using a Gprogram called "Porp1ate.c". With a fixed porosity of 23% and by fixing the AR together with the dimensions (length, width and the thickness) of the plate, this program calculates the hole-diameter and the number of the holes required to satisfy the AR and the porosity constraint. The holes were arranged in staggered rows (similar to honeycomb arrangements) and were evenly spaced. In Appendix C, the source code for "Porp1ate.c" and some outputs are presented. Plate dimensions of 8.0 inches by 4.0 inches with a thidcness of 0.06 inches was used. Aspect ratios of 4 and 5 resulted in hole diameten of 0.015 inches and 0.012 inches and the corresponding number of holes of 41649 and 65076, respectively. The AR, which resulted in a lower number of holes was

chosen since it translated to a lower cost for the plate.

Table 2.1 lists the hd ized design parameters for the porous plate. The aluminum porous plate is only the outer part of the MBT skin. For the inner plate a similar

arrangement to the NASA Lewis plate was followed. High density polyethylene (HDPE) inner plate, as shown in Figure 2.2, was used to distribute the blowing air evenly. Initially,

Table 2.1: A Sumrnary of Porous Plate Data

Design Parurneter Lengt h Width Thickness AR Porosity Number of Holes Hole Size

MBT runs with only the porous plate were attempted. The HDPE inner plate was later added to the outer porous plate with no gap between the two plates.

Parameter Data 8.0 inches (20.32 cm) 4.0 inches (10.16 cm) 0.06 inches (0.1524 cm) 4 23% 41760 (145 x 288) 0.015 inches (0.0381 cm)

2.2.3 Plenum

A plenum is needed to allow air to distribute evenly before it exits through the porous plate. A simple box construction is used as the plenum for the UTIAS-MBT model. The size of the box is constrained by the porous plate size. This box fits perfectly inside the frame made to secure the porous plate on to the main-body frame. The plenum box's height is restricted by the size of the aiuminum U-channels used as the fiame. Figure 2.6

is an AutoCADTM drawing of the plenum design. Four holes are for the flexible tubes, which convey the blowing air fiom the blower.

2.2.4 Model Span

It was decided that the model would span the test section of the tunnel from top to the bottom. This was because the model had to be positioned perpendicular to the traversing ami where the pressure probe is secured. This also allowed the model to be secured firmly to the tunnel top and the tunnel bottom by its two ends. Thus, the span

of the model waa the same as the distance from the top of the tunnel to the bottom of the tunnel. Distance was 24.4 inches (61.98 cm).

2.3 Model Construction

The UTIAS-MBT model was constructed at the LOW Speed Aerodynamics Lab. The

leading-edge (LE) and the trailing-edge (TE) construction consisted of Styrofoam core (cut-outs) covered with two thin fiberglas layers. The fiberglass layers provided the

necessary hardneas and smoothness. Since this is a 2-D model, cut-outs from Styrofoam blocks provide qui& and accurate model components (LE & TE). The main-body sec-

tion was constmcted of duminum U-channels and aluminum sheets. Each section was constructed separately and was connected by the balsa strips and epoxy. The following

sections describe the construction process of each of the model components as well as their final assembly.

2.3.1 The Leading-Edge and The Trailing-Edge

The LE and the TE utiliied ~ t ~ r o f o a m eore and fiberglass layer construction. Exactly

the same steps are involved in building both components of the model. One difference

was the leading-edge nose where the LE nose had a very high curvature. The LE nose was very difficult to shape by hot-wiring. After several trials with Styrofoam cutting,

an elliptical balsa nose was used to give a consistent 2-D nose. Figure 2.8 shows clearly

where the Styrofoam was replaced by the balsa nose.

Listed below are the construction processes involved in building the LE and TE. First,

the process of producing a Styrofoam 2-D model components using the hot-wiring process

is described .

1. Prepare two templates of the component to be constructed.

Print two full-male drawings of the part to be constructed on paper.

Prepare two thin sheets of aluminum (aluminum should be flat and fairly stiff).

0 Paste the printed part drawings on each aluminum piece.

a Wait until the paper is completely dried.

0 Cut the aluminum pieces using a band-saw confoming to the part shape as closely as possible.

a Sand away the rough edges and unwanted aluminum and paper. Srnoothness is very important. Any rough edge will result in bad Styrofoam cut-outs.

0 Put some markings on the prepared templates to cal1 out when hot-wiring.

Two people who are hot wiring need to synchronize the travel of the hot-wire.

Pay attention to each person's point-of-view when applying markings on the

t emplates.

0 Drill two holes t o secure the templates on the Styrofoam block

2. Prepare a Styrofoam block.

Prepare a block of Styrofoam appropriate for the part being made.

Secure the templates, one on each end of the Styrofoam block.

3. Hot-winng (This step requires two people).

Find a bench or a platform which is narrower than the Styrofoam block being

cut.

a Place a counter-weight on top of the Styrofoam so that the Styrofoam stays

still during hot-wiring.

a Test hot-wire on a scrap of Styrofoam to see if the desired cutting temperature

is achieved.

a Discuss with the partner and plan a etrategy. One person should cal1 out the

marking number.

a Slowly move along the template. Start and lift at the same time. Multiple cuts

might be better than one single cut depending on the shape of the template.

The above three steps complete the process of producing a Styrofoam core for the mode1 component of interest. Figure 2.7 is an example of a successfully cut LE Styrofoam

core. Next, the fiberglass layers must be applied over the 2-D Styrofoam cores. The

following steps describe the fiberglass layering process .

1. Fiberglass preparation.

a Select a fiberglass grade to use and cut to size. Fiberglass should be large

enough to cover both sides (top and the bottom) of the Styrofoam core. This

is especially important for the LE.

Place the Styrofoam core on the stand prepared. For the LE the nose should

be pointing up.

2. Fiberglass application.

a Prepare a batch of e p o q mixture, (resin & hardener), in a plastic cup. Stir well with a stir-stick. Tky to use an epoxy mix that gives fairly long working

time.

a Wear latex gloves and have plenty of paper towels to wipe dripping epoxy fmm the work bench.

O Using a spatula apply epmcy carefully fiom top to bottom, (i.e. from nose d o m for LE). Do try to prevent dripping. Apply evenly and swiftly.

a If a second layer of fiberglass is needed, apply promptly after the first layer.

O Check in ten or twenty minutes for any bubbles and irregularity on the surface.

a Let cure over nigbt.

Figure 2.8 is a picture of the LE section after the fiberglass application.

Once these sections are coated with the fiberglass, they are cut to desired span and length and joined with the main-body section frame to form a complete model. This finished model still requires a final finishing touch with sanding and painting.

2.3.2 Main-Body Section

The main-body section was made from six aiuminum U-channels. Two longer U-channels formed the spanwise pieces. Four shorter U-channels formed the chordwise pieces. Two spanwise U-channels and two chordwise U-channels formed a box-like frame for the main-

body section (see Figure 2.9). The other two chordwise U-channels were used as the chordwise platforrn for the porous plate mounting. The main-body frame was sand- wiched between aluminum sheets. One large sheet was placed on the side without any porous plate. On the side where the porous plate was inserted, two smaller aluminum plates covered parts of the frame, while the porous plate filled the rest. The main-body construction can be seen in Figure 2.1 and Figure 2.9.

2.3.3 Plenum for Porous Plate

The plenum was built using a thin sheet metal. The drawing in Figure 2.6 was printed and pasted on a sheet of metal. The sheet metal was then cut and folded to form a box with four lips. The lips were later screwed onto the frarne with the porous plate. Four corners of the box were held together with four rivets. Four holes for the flexible tubes were ddled once the box is formed. These holes are the inlets to the plenum

for the blowing air. b e r corners were sealed by silicon sealant to prevent any leakage. Figure 2.10 is a picture of the plenum inside the finished model.

2.3.4 Final Assembly and Final Finish

Final assembly of the model was t n ~ i a l once d l the components were built. Fint , a spanwise aluminum U-channel was glued and screwed onto the leadingedge. As mentioned previously, a balsa strip was used in between the Styrofoam core and the aluminum

channel for better adhesion. The same steps were repeated with the trailing-edge. This

produced two bigger components: the LE with an aluminum U-channel and the TE section with the other long U-channel. These two cornponents were brought together by

two short U-channels forming a frame. This formed a box of aluminum channels with two Styrofoam components attached to its sides. The other two short U-channels were placed near the middle of the main-body frame. They were placed exactly 4 inches apart to accommodate the plenum and the porous plate. These formed a platform where the porous plate would be inserted. After the platform was finished, the aluminum plate was

screwed on the frame on the side opposite that for the porous plate. Next, the plenum

was inserted and the flexible tubes were connected to this plenum.

Once ail the different components were assembled a final finish was needed. The fiberglass layers were sanded and painted with lacquer spray paint. This gave the model

a smooth and shiny finish. The completed model is shown in figure 2.11. The porous

plate and the solid plate were inserted when it was time for the traverse.

Figure 2.5: Drawing of the Porous Plate Selected

Figure 2.6: Drawing of the Plenum Box

Figure 2.7: Picture of a Successful LE Styrofoam Core

-

Figure 2.8: Picture of the LE Component After the Application of Fiberglass

- - - - - - - -

Figure 2.9: Picture of the Main-Body Section Rame

Figure 2.10: Picture of the Plenum

Figure 2.11: Picture of the Completed Mode1

Chapter 3

Experiment and Analysis

The main objective of this experiment was to study the effect of MBT on the UTIAS- MBT model profile drag at zero angle of attack. This chapter describes the experimental method used, the set up of the experiment, and the facilities.

3.1 Wake Traverse

Measurement of drag on the UTIAS-MBT Mode1 required an accurate and simple method. This also required a measurement method which presented least problems with the blowing system. There was no balance installed in the tunnel and it would have been difficult

to build and install a balance that is not Sected by the blowing system. Wake-traverse was selected for its relative simplicity, proven reliability and its ability to be independent of the blowing system. Wake traverse is also known to give the best two-dimensional drag measurements.

Another naxne for the wake traverse is the mornentum deficit method. It is a method in which momentum of the airflow before and after the model are measured and compared to deduce momentum loss. This momentum loss is translated into the profile drag of the model. A complete traverse starts on one side of the model, far away from the model, and

moves in predetermined steps towards the other side of the model. During this traverse, pressure measurements are made in the wake of the model. At each step, four pressure measurements and position data are recorded. These measurements are used to calculate the drag using the formula by Jones[5]:

CHAPTER 3. EXPERIMENT AND ANALYSIS

Figure 3.1 : UTIAS Aeroscoustics ninnel Facility


where

Cd = profile drag coefiicient 91 = total pressure at wake station

= static pressure at wake station pm = free stream static pressure q, = f'ree stream dynamic pressure

C = normalized y-dist ance (y-axis is the traversing a i s )

This equation is only valid for cases without any blowing. Equation 3.1 has to be

modified to accommodate the mass injection by blowing. This is easily done by subtracting the mass flw added by the mass injected. The following equation reflects the required modification.

where

mb = mass flow rate of blowing air U, = free stream velocity b = porous plate span (width) c = mode1 chord length

Mass flow rate (hb) is defined as

where

pb = density of the blowing air A,= exit area of the porous plate Ub = blowing speed

Equation 3.2 and 3.3 indicate that the blowing speed must be rneasured. Since the blower set ting st ays constant throughout the whole traverse, an average blowing speed

(i.e. average for a complete traverse) is used for the drag calculation. Profile drag of the model is obtained by first calculating the first tenn in equation 3.2. This is a simple integation of the integrand. Next the blowing speed is used to cdculate the average mass flow rate for the particular traverse. Using this mass flow rate, the second term of

equation 3.2 is calculated and this term is subtracted from the first term. This is the 2-D profile drag in coefficient form for the model. When there is no blowing, equation 3.2

simply reduces to equation 3.1.

3.2 Pressure Measurements

Equation 3.1 required four pressure measurements: the total pressure at the wake station

(g2), the static pressure at the wake station b), the free stream static pressure (p , ) ,

and the free stream dynamic pressure (q,). Pressures were measured by using multitube

water manometers and semiconductor pressure transducers. A pitot-tube was used to measure the dynamic pressure, the static pressure, and the total pressure in the tunnel.

Another pitot-tube was used for blowing speed measurements. Al1 pressure measurements

were performed using semiconducter pressure transducers. Multitube manometers were

used as a back-up for the dynamic pressure measurements of the wake. These pressure

measurements were al1 recorded either in electronic form or on paper.

3.2.1 Dynamic Pressure

A pitot-tube and a differential pressure transducer called MPX501ODP, manufactured by

Motorola, were used to measure the dynamic pressure in the wake. Dynamic pressure

is the differential pressure between static and total pressure. A pitot-tube allows one

to measure the total pressure and the static pressure in the airflow. Two ports from

the pitot-tube were connected to the ports of the MPX501ODP to measure the dynamic

pressure (Q). For eadi measuring point in the wake, 100 to 300 scans of pressure measure-

ments were made. These measurements were averaged and recorded in a file. An AST386 computer and RTI-800 data acquisition card, (rnanufactured by Analog Devices), were

used to record voltage output fiom the pressure transducers. MPX5010DP translates

the dynamic pressure in the wake to voltage. This voltage was read by the RTI-800 and

was converted to a digital signal which the AST386 recorded.

The calibration of MPX5OlODP wds carried out at UTIAS Low Speed Aerodynamics Laboratory and Aeroacoustics h e l . The tunnel in the Low Speed Aerodynamics

CHAPTER 3, EXPEFUMENT AND ANALYSIS 24

Laboratory provided air speeds below 70 fils (20 m/s) and the Aeroacoustics Tunnel provided air speed above 150 ft/s (45.72 m/s). Figure 3.3 is the calibration result. The calibration ailows for conversion of the voltage output to dynamic pressure. Dynamic pressure is easily converted to velocity by the following formula.

where

V = air speed

Q = dynamic pressure measured

p. = density of air

Dynamic pressures were calculated in two different ways. First, it was calculated

using the MPX501ODP readings. Secondly, it was found by using the back-up water manometer readings. When dynamic pressures were rneasured from MPX50 10DP read-

ings, the calibration graph shom in figure 3.3 was used to obtain Q. A second method

was to use a formula provided by Motorola. The conversion formula was obtained from

Motorola Technical Data Sheets. Dynamic pressure calculated from the MPX5010DP reading was named Q for data tables presented in appendix A. When dynamic pressures

were calculated fiom water manometer readings, a simple hydrostatic relation was used.

where

pw = density of water (1000 kg/m3)

g = acceleration of gavity h = water column height (total head reading - static head reading)

Dynamic pressure calculated using the above equation was named P d H 2 ~ a9 presented

in Appendix A.

CHAPTER 3. EXPEUMENT AND ANALYSIS 26

3.2.2 Static Pressure

A pitot-tube has two pressure ports which are used to measure dynamic pressure. One

of the ports measures the static pressure. This static pressure was meaaured using an absolute pressure transducer called MPX4115A. For some earlier tests, a different kind of

pressure transducer, an MPX2100AP) was used. This was later changeà to an MPX415A because the latter transducer had a higher pressure range and better output signal, which

were more appropriate for the test. Using a T-connecter, the static pressure port w u connected to the absolute pressure

transducer, MPX4115A. Again the static pressure was scanned 100 to 300 times by the

RTI-800 data acquisition card and was averaged to give a single reading for the corre sponding traverse location (Y-location). The calibration for MPX2100AP was carried

out using the vacuum pump facility at the UTIAS Fusion Research Group. The result

of this calibration is shown in Figure 3.4. This calibration was used to convert the voltage reading to absolute pressures for al1 MPX2100AP readings. When the MPX4115A was used to measure static pressure, the transfer function supplied by Motorola (see

Figure 3.5) was used to convert voltage readings to absolute pressures. Static pressures

measured using semiconductor pressure transducers are named P, in Appendix A. A second method of calculating the static pressures was attempted. This was done

in two steps. First, static pressure for the wind-tunnel off case was recorded. This is

the atmospheric pressure of the tunnel test-section (Pa,). Next, the static pressure

readings from the water manometers were subtracted from this atmospheric pressure. This provided the static pressure for the corresponding location in the wake.

Water manometer measurements are al1 relative to the tunnel atmospheric pressure

(water manometer readine are not absolute measurements) and it is lower than P&, when the tunnel is on (i.e. in the wake of the model). Therefore the water column reading

is subtracted from Pst,. Static pressure measured using this method is termed P8H20 in

the data tables presented in Appendix A.


Pressure (tek to sealed vacuum) in kPa

Figure 3.5: MPX4115A Transfer hinction (from Motorola Technical Data Sheets)

3.2.3 Total Pressure

Total pressures were not measured but derived. They were derived from dynamic pressure

and static pressure measurements. Total pressure is simply the sum of dynamic pressure and static pressure. Two different methods were used to find total pressure for each traversing location. Total pressure was calculated by adding Q (dynamic pressure from MPX5010DP reading) and P, (static pressure from MPX4115A or MPX2100A.P) to give

Ptl. Similarly, total pressure derived from the sum of Q and (static pressure rneasured by the multi-tube water manorneter) gives Pa.

3.2.4 Blowing Speed

Blowing speed is measured by using a pitot-tube and a differential pressure transducer

as indicated in Figure 3.6. Air speed from the blower is much lower than the air flow

in the tunnel and this requires a differential pressure transducer with lower operating pressure range. A Honeywell164PC Low Pressure Sensor is used to measure the dynamic

pressure in the blowing system. Velocity is calculated using Equation 3.4. Density of air

was assumed to be the standard density of air at sea level (p. = 1.225 kg/m3). Many different apparatus were tested for measuring the blowing speed. Most of them

were inadquate for the purpose of measuring blowing a i . speed. First, an inclined water

CHAPTER 3. EXPERIMENT AND ANALYSIS 29

manometer with 0.1 inch full-scale range waa used. This manometer gave fairly good results until the inner HDPE plate was inserted. Next, a micro-manometer was used to measure blowing speeds. This was a very old instrument which had not been used for very long time. It provided inconsistent readings and was unreliable. Lastly, a Honeywell

164PC Low Pressure Sensor nms used to measure blowing speeds with the HDPE inner plate inserted. This pressure transducer gave consistent readings. It was thus decided that Honeywell 164PC Low Pressure Sensor was to be the measuring device.

The Honeywell164PC Low Pressure Sensor was calibrateci at Low Speed Aerodynam- ics Laboratory. A Dwyer water manometer was used to measure the dynarnic pressure. Figure 3.7 shows the resulting calibration graph.

3.3 Position Measurement s

The Aeroacoustics T'unnel had three traversing arms al1 equipped with stepper motors and a stepper motor controller built by Velmex Inc. Communication with this aged Velmex 8300 series controller[6] could not be established and the traversing arm was manually positioned. Measuring the position of the pitot-tube during the wake traverse was not difficult. Measuring the position of the traversing amn was the same as measuring

the position of the pitot-tube. This is because the pitot-tube was taped at the end of the traversing m. A d e r was taped on the side of the traversing arm and the positions were manually read from this d e r . This is shown in Figure 3.8 with the traversing a m .

A ceiling fan speed controller was installed to the leaf blower. This allowed a variable control of the blower. The fan speed controller has a control knob which only has a

travel of 270 degrees. A dia1 with 15 degree increments was drawn. These increments

were numbered from 1 to 18 and were used as the blower settings. The blower did not start at settings below 5. Therefore, settings bom 1 to 4 were not used during the experiment. The lowest possible blower setting was five (BSO5). Blower settings of 5, 8,

10, 13 and 15 were used to study the effect of the MBT on the mode1 profile drag. Besides the blower settings, a water filter was installed in the blowing system to

reduce the air speed of the blower. This is shown in Figure 3.6. A HDPE inner backing plate also reduced the blowing speed and distributed the blowing air evenly.


Table 3.1 : Channel Assignments on RTI-800

3.5 Data Acquisition

Data acquisition dunng the wake traverse was perforxned with a data acquisition card (RTI-800), installed in an AST386 personal computer. RTI-800[7] was capable of measuring 16 differentid inputs. Only four of the 16 channels were used. Channel assignments are listed in Table 3.1. For each Y-position of a traverse, each channel was scanned for

100 or 300 times. Readings for al1 four diannels were averaged and this average was

used to calculate the drag. Position data and multi-tube water manometer readings were

recorded on the run chart manually. A Basic program was written for automatic scanning of the four channels. This Basic

program initiated and repeated the scanning process for a required number of times (usually 300 tirnes). For each scan, analog voltage reading on each channel was converted

to a digital signal and stored in an ASCII file. Appendix D provides the program listing

for this basic program.

3.6 Run Grid

Three sets of runs were used to investigate MBT. The first set of runs were for a solid plate insert. They were the baseline drag values: Cdborc A drag reduction is achieved

if the profile drag is lower than A second set of runs consisted of traverses with

just the outer porous plate inserted. Lastly, a set of runs with a HDPE inner plate as a backing to the aluminum porous plate was conducted. Table 3.2 is a surnmary of runs

conduct ed.

BDSOLID = Baseline drag for soiid plate PLUG = Pipes leading into the model plenum are dionnected and plugged = Unblown porous plate UNPLUG = Pipes leading into the model plenum are connected and unplugged = BSOO PO4 = Porous plate insert with tunnel fan setting at 04 BS = Blower set ting WI = Porous plate, Water filter on, HDPE inner plate on

Plate Qpe

SOLID PLATE POROUS PLATE POROUS PLATE (WI)

Table 3.2: Run Grid

Run Code I

WI04BS15

BDSOLIDl PO4WPLUG WOQPLUG WIû4BS13

BDSOLID2 POQWWNPLUG WI04BS00

BDSOLID4 P04BS08 WI04BS08

BDSOLIDS P04BS05 W104BS05

P04BS10 WI04BS10

CHAPTER 3. EXPERIMENT AND ANALYSIS 35

Figure 3.9: Picture of the 'Itaversing A m in the Wake of the Mode1 (Zero Position)

3.7 Wake Traverse Procedure

As its name indicates, the wake traverse is simply the act of traversing across the wake

of a model. For a twedimensional model, this ia even simpler. Only one axis traverse is needed to determine the profile drag of a model. Figure 3.9 shows the traversing arm

and the model in traversing mode. This section describes the travening procedure used for the study of the MBT at UTIAS.

One complete traverse usually took about 30 to 40 different measuring locations depending on the set-up. For example, if the traverse was for solid plates, the wake shape was smdler and it required smaller increments of Y-location near the wake. If the traverse was for a case with blowing on, the wake was larger and a stepping scheme

which was suitable for that wake had to be used. The stepping scheme was determined by doing a quick and continuous traverse. This quick traverse allowed one to see how the wake might look like. During this quick traverse, the RTI-800 data acquisition card was allowed to record time, scanning number and dynamic pressure. This information with

traversing a m speed was used to guess the wake boundaries. This then gave a qui& picture of where the traversing increments should get smaller and larger. Once traversing locations were determined, it was time for a more through traverse.

Following are the detailed steps used to do one complete wake traverse.

CHAPTER 3. EXPEIUMENT AND ANALYSIS

1. Ascertain the tunnel exit is free of obstruction.

2. Turn the tunnel circuit breaker switch on.

3. Verify that there are no loose connections in plumbing of the pressure ports.

4. Check zero level of the multi-tube water manometer and record this zero level.

5. Move the traversing a m (pitot-tube) to zero position.

6. Do a zero run. This is one complete scanning of the four channels described in

table 3.1).

7. When scanning is complete, record averaged data and manometer readings on the

run chart.

8. nirn the tunnel on and wait for few minutes.

9. Turn the blowing system on for the blower on cases. Do a blower on zero.

10. Starting from the zero location (first Y-location), scan 4 channels for 300 (or 100)

times. Once the scanning is complete, record the averaged data on run chart. Move to a new location and wait at least 15 seconds before starting the next scan. Repeat

t his step until al1 the Y-locations are traversed.

11. While the computer is scanning, read manometer readings and record manually on

run chart.

12. Move the traversing a m to zero location and do a scan.

13. Turn tunnel off and wait 5 minutes or so. Make sure the tunnel circuit breaker

switch is in the off position.

14. Do an end zero run.

For every Y-location of the traverse, an ASCII file with four columns of data was

produced. So for one complete traverse, about 30 to 40 files were created. These data

files were copied to floppy disks and later processed using personal computers at the Low

Speed Aerodynamics Group.

Chapter 4

Results and Discussions

Three sets of traverses were completed at the UTIAS Aeroacoustics T'unnel. The objective of the fint set was to determine the baseline drag. Baseline drag was the drag of the UTIAS-MBT mode1 with solid plate insert. Their nin codes al1 started with "BDSOLID" , meaning baseline drag for solid plates. A second set of traverses were for porous plate

cases with no inner backing plate. The run codes for these cases al1 started with just "P" for porous plate. The third set of traversing runs were for porous plate with HDPE inner backing plate. These runs al1 had run codes starting with "WI" indicating the set up of the test. "W" was for water filter and "1" was for HDPE inner plate. Data from each set of nins are presented in tabular format in Appendix A.

The post processing of the data was conducted with the personal computers available in the Low Speed Aerodynamics Group. Microsoft ExcelTM was the tool for d l the necessary conversions and calculations. MATLAB*~ was used to integrate the integrands

across the wake. This integral was later fed back into ~ x c e l * ~ to calculate the profile drag of the model.

Tables A. 1 to A.43 were al1 produced using ~ x c e l ~ ~ . As seen from the run data tables, for example in Table A.28, one traverse consisted of 30 to 40 measuring points

(Y-locations). In Table A.28, it took 39 runs to complete one traverse. When a traverse was completed, the run data, which were al1 in volts or inches of water, had to be converted to appropriate units (e.g. Pascal (Pa) for pressure readings) . Each run, (each Y-location), returned an averaged value of the following variables: Pd, Va, P. and Pdb- These variables were al1 recorded in an electronic data file. A . ~ x c e l * ~ macro was used to read only the averaged values fkom these electronic files. Y, PtHao and were

al1 recorded manually on the run chart during the traverse. They were later typed into the appropriate columns in nui data tables.

CHAPTER 4- RESULTS AND DISCUSSIONS 38

Once al1 the data were gathered for one complete traverse, the calibration gaphs presented in chapter 3 and ~xcel~' , were used to convert voltages to pressures. First, PnNZO readings were subtracted from Ptszo to calculate PmZO. Next, al1 the readings from the semiconductor pressure tramducen were converted from voltages to Pascal. Static pressures and the total pressures were dl calculated using the method described in chapter 3.2. Normaüzed Y-distance, C, wu dso cdculated.

When dl the data conversion was completed, the integrand shown in the first term of equation 3.2 was calculated for each Y-location. These values were later integrated to give CdtuoLc An example of this calculation is Table A.29. Integration was done for

wake boundaries of Y= 35.00 cm (C= 0.70) and Y= 20.00 cm (C= 0.40). Two different integrands were cdculated. One integrand used Pt which was derived purely from the

semiconductor pressure transducer measurements. A second integrand was found by

using Pa which is a sum of Q and Pnxzo. It was later used for final drag calculation because it was more consistent. Measurement at the boundaries of the wake traverse (at Y= 35.00 cm and Y= 20.00 cm) were considered as the free-stream values. This was

a safe assumption since the pitot-tube was far away from the actual mode1 wake. This is shown by the inMnance (flat region of the wake) of the integand profiles. After the

completion of the integand calculations, a numerical integration function called "trapz" in MATLABTM was used to integate d l the integrands in the boundaries specified above. The resulting integral was Cdwahr.

The second term of equation 3.2 was calculated using Pd measurements. Since the

blower setting remained constant throughout the whole traverse, an average for al1 the tunnel-on cases were calculated. This was the blowing dynamic pressure with the tunnel on. A zero reading (blower off, tunnel off readings) of the pressure transducer was needed. This was found by averaging two zero runs at the beginning and at the end of a traverse. Blowing dynamic pressure (Pdb) were converted to h d blowing speeds (b), mass flow rate (rizb) and the blowing parameter (2). Using this mass flow rate CdMOWinO was calculated.

The profile drag, Cd, was calculated by subtracting Cawing fiom Cdwokc. The following sections present the reaults obtained by the three dinerent sets of traverses. Caution must be used when interpreting the second set data which had only the outer porous

plate inserted. Blowing speeds measured for these traverses were inconsistent. Thus,

Caming values and Cd values for these cases are questionable. This set was included only to show the integrand profile. Blowing speed measurement for the traverses with HDPE inner plate cases were consistent. Therefore, the cases for the effect of MBT with

a porous plate and HDPE inner backing are discussed.

CHAPTER 4. RESULTS AND DISCUSSIONS

4.1 Baseline Drag

Four traverses of the baseline configuration of UTIAS-MBT were completed. They were named "BDSOLID 1" , "BDSOLID2", "BDSOLID3" and "BDSOLIDI' . Figure 4.1 and

Figure 4.2 show the integrand profiles of these solid plate runs. Cd of 0.0082, 0.0077,

0.0074 and 0.0082 were obtained, respectively. Average of these values is 0.0079. A standard deviation of 0.0004 was calculated and was used as the error for al1 drag values obtained. No blowing was used for this run and therefore there is no CdblOUIing. Cdhrc for

the UTIAS-MBT model was 0.0079~0.0004.

Ch,e was compared to the widely published profile drag results of H.B. Squire and A.D. Young (Figure 25.3 of Reference [5]). The profile drag of a 5% thick symmetrical model with a transition location of approxirnately 20% chord was reported t o be 0.0083.

This is remarkably close to Che of 0.0079I0.0004.

Figure 4.3 is a gaph of integrand profile showing al1 four traverses. It indicates that

most of the variation in the wake profile occurred in two regions: the center of the wake

and the region bounded by != 0.58 and := 0.68. Due to this vaxiation the drag value

obtained had approximately 5% (0.0004) error.

4.2 Traverses with Outer Porous Plate Only

A second set of traverses with only the outer porous plate insert were conducted. Un- fortunately, the blower speed measurement at the tirne of the test were unreliable. As

a consequence, CdMauinp values are probably not correct. Therefore only the integrand

profiles are presented and the results d l not be discussed here any further. Figures 4.4

to 4.6 show the integrand profiles obtained.

4.3 Traverses with Porous Plate and HDPE Inner

The most interesting results of this project came from the last set of traverses. A porous

plate insert with an HDPE inner backing plate was used . This was similar to the porous

plate wed at NASA by Hwang. The biggest difference was that there was no gap between

the aluminum porous plate and the HDPE backing plate. Several blower settings were explored for this set.


BDSOLIO1: Drag = 0.0082

Figure 4.1: Integrand Profile of Solid Plate Traverses 1 and 2

BDSOLID2: Drag = 0.0077

0.2

u C

C

C - 0

I 1 1 I I 1 I I I

- . . . . . : . . . . . . .: . . . . . . . . . . . . . . .: . . . . . . ' . . . . . . . .:. . . . . . . . . . . . . : . . . . . . . . . . . . -

- . . . . . . . . . .

- . . . . . . . . . . . . . . . . . . . . . . . . - 1 I I 1 1 1 1 I 1

0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 YIC


0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 YIC

BDSOLID4: Drag = 0.0082

Figure 4.2: Integrand Profile of Solid Plate 'ilaverses 3 and 4

0.2

I I I I 1 1 I I I

. . . . . . . . . . - - - . . . . . . . - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . : : . - -0 C (d

g0.1 - . . . . . . . . . . .

C

c - 0 - . . . . . . . . . . . .

Figure 4.3: Integrand Profile for Al1 Solid Plate Cases

P04WUNPLUG: Cdwake = 0.0121, Cdblowing = 0.0048, Cd = 0.0073 I I I I 1 I 1 I I I 1

P04WPLUG: Cdwake = 0.01 23, Cdblowing = 0.0000, Cd = 0.01 23

ENowieg, System Unplugged (Blower Off) . . . .

0.2-

Figure 4.4: Integand Profile of Porous Plate without HDPE Inner Plate Cases: P04WLUG and P04WUNPLUG

I I I 1 1 I I I I I

: lowing system Plugged (Unblown Porous Plate) . . . . . : . . . . . . . . . . . . . . - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . : . . . . ; . -

2 !! $0.1 - .:. . . . . . . . . . .

C C -

0 - . . -


P04BS05: Cdwake = 0.0129, Cdblowing = 0.0048, Cd = 0.0081

P04BS08: Cdwake = 0.0129, Cdblowing = 0.0053, Cd = 0.0076

0.2

u C tu b0.1 9 C -

0

Figure 4.5: Integrand Profile of Porous Plate without HDPE Inner Plate Cases: P04BS05 and P04BS08

r 1 I I T V I I 1 I

: Blower Settiig 05 : - . . . . .: . . . . . . . .; . . . . . . :. . . . . . . .:. . . . . . . . .:. . . . . . . .:. . . . . . . . :. . . . . .; . . . . . ; , . . . -

- . . . . . . . . . . . .

- . . . . . . . . . . . . . . . . . . . . . .

1 I 1 I 1 I 1 1 1

0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8

Figure 4.6: Integrand Profile of Porous Plate without HDPE Inner Plate Case: P04BS10

PO4BSlO: Cdwake = 0.01 23, Cdblowing = 0.001 6, Cd = 0.01 O7

0.2

1 I I 1 I I 1 I 1

Blower Setting 10 : - . . . . . . . . . . . . . - . . . . . . - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -

m g0.1 - . . ; .

. . . . . . . . . . . . C C -

. . . . . . 0 - . . . . . : . . . . . . .

CHAPTER 4. RESULTS AND DISCUSSIONS 45

The blower settings used were 00, 05, 08, 10, 13, 15. A traverse with the blowing system plugged was also done. Drag from the plugged traverse case allowed for measurement of the drag of the unblown porous plate. This was called Cdp. Integand profile

for the plugged case is shown in figure 4.7. Cd, measured was 0.0085. The ratio of Cdp to Cdboia was 1.0759. This meant that the porous plate with holes introduced a 7.6%

increment in profile drag. This was less than 10% requirement that Hwang mentions for a good MBT skin. Thus, it was concluded that the UTIAS-MBT model's porous plate is

a good MBT skin. A summary of drag results with the mass flow results are tabulated in table A.43.

Figures 4.8 to 4.10 show the integand profile for al1 the cases with any m a s flow.

The "WI04BS00" case was the case with the blower turned off but some mass flow existed

due to the difference in tunnel test section static pressure and the atmospheric pressure outside the tunnel. This is why the blowing system had to be plugged to obtain Cdp for

the porous plate.

4.4 Summary of Measured Drags

Drag coefficients obtained from traverses with the HDPE inner plate were divided by the baseline drag, These drag ratios were graphed with blowing parameters.

First, a g a p h of the profile drag with varying blowing parameter was plotted, as shown

in figure 4.11. This clearly showed that profile drag with no blowing was higher than

the baseline drag value of 0.0079. However, with some blowing the drag was reduced to

below that of the baseline drag. This was clearly shown when drag ratios (Cd/Ck.,) were plotted with the blowing parameter (see Figure 4.12). Any value below one meant that the profile drag of the particular case was lower than the baseline drag value. Tkaverses with blower settings of 05, OS, 10 and 15 had drag ratios below one. "WI04BS05"

showed the most drag reduction. The profile drag was reduced by approximately 6%

with a blowing parameter value of 0.39 (kg/s/m2). Another interesthg trend to note was the effect of blowing on Cdwafc and CdblOUIina

This is shown in figure 4.13 and figure 4.14.


WIWPLUG: Cdwake = 0.0085, Cdblowing = 0.0000, Cd = 0.0085

: Blowing Systerri Plugged, Unblown PorolZs Plate Case : . . . . . . . . . . . . . . . . . . . . . : . . . . . . . - m . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " .

Figure 4.7: Integrand Profile of Porous Plate with HDPE Inner Plate Case: WIOWLUG

4.5 Error Analysis

For enor determination of the drag values, four runs with exactly the same setup was

carried out. This was done for the solid plate case only. Error was determined to be one standard deviation of the drag values measured. The standard deviation of the drag values for the solid plate (i.e. base drag) cases was 0.0004: four drag counts. Al1 the

drag numbers presented for blowing on and solid plate cases were considered to have this error in their values.


W104BS00: Cdwake = 0.0092, Cdblowing = 0.0012, Cd = 0.0080 1 1 I 1 I 1 1 I 1

y Blouiw Setlihg 00 0.2 - . ; . .: :. .: .:. . . . . . . . . . . . . . . . . . . . . . . . . . . . ' . . . . ' -

W104BS05: Cdwake = 0.0087, Cdblowing = 0.001 3, Cd = 0.0074

: Blower Settirig 05 : , . . . . . . ,;. . . . . . . ; . . . . . . . . . . . . . . . . . . . . . . . . .:. . . . . . . ;.. . . . .; . . . . . . : . . . . .

Figure 4.8: Integrand Profile of Porous Plate with HDPE Inner Plate Cases: WI04BS00 and WI04BS05


W104BSûû: Cdwake = 0.0091, Cdblowing = 0.001 5, Cd = 0.0076

W104BS10: Cdwake = 0.0093, Cdblowing = 0.001 6, Cd = 0.0077

Figure 4.9: Integrand Profile of Porous Plate with HDPE Inner Plate Cases: WI04BS08 and WI04BS10

0.2-

b

s p)J C C -

0 -

- - 1 1 1 1 1 1 I 1

Blower Settiog 10 . . . . . ; . . . . . .; . . . . . . - . . . . . . . . . . . . . . . . . . . . . . . . . : . " . . . . . . . . -

- . : . . . . . . . . . . . . . . . . . . . . . . . . _ _ . _ . . _ . . . . . _ . . . . - . . . .

. . . . . . . . . . . . . : . . . . . . - . -

i 1 1 1 I 1 1 1 1

0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 YIC

CHAPTER 4, RESULTS AND DISCUSSIONS

W104BS13: Cdwake = 0.0099, Cdblowing = 0.0016, Cd = 0.0083

WIO4BS15: Cdwake = 0.0089, Cdblowing = 0.001 3, Cd = 0.0076

Figure 4.10: Integrand Profile of Porous Plate with HDPE Inner Plate Cases: WI04BS13 and W104BS 15

Figure 4.11: Profile Drag Variation with the Blowing Parameter

Chapter 5

Conclusions

A very interesting skin friction reduction technique called the Micrc+Blowing Technique (MBT) was investigated. A two-dimensional symmetrical model, the UTIAS-MBT, was

developed for the purpose of applying the MBT, and thereby evaluating its effect on the model profile drag.

The UTIAS-MBT is a 6.4% thick model with a total chord length of 19.5 inches

(0.4953 m). This model consisted of three sections: the leading-edge, the main-body and the trailing-edge. A porous plate with 23% porosity was inserted over the plenum built in the main-body sections. MBT was applied through this porous plate.

Three sets of wake traverses were perforrned. These three sets of traverses differed by the type of inserts, (i.e. solid plate, porous plate or porous plate with HDPE inner plate), placed over the plenum in the main-body section. The first set consisted of four solid plate runs. An average of the solid plate cases was used as a baseline drag. Al1

measured profile drags with the porous plate inserts were compared to this value. The second and third sets of traverses involved blowing or mass injection through two different configurations of the porous plate. The second goup of traverses was done with a porous plate which had no inner plate. Blower settings of 00, 05, 08 and 10 were used. One

traverse with the blowing system plugged was included. This plugged case allowed for the measurement of the change in the profile drag of the model due to the porous plate (i.e. unblown porous plate case). The last set of traverses applied MBT through a porous plate with an HDPE inner plate. The MBT skin had two layers: outer porous plate and

the HDPE inner plate. Blower settings of 00, 05, 08, 10, 13 and 15 were used. This was

the most interesting set of dl, because it included the drag reduction cases.

The baseline drag was measured to be O.OO79f 0.0004. The drag of the model with the double layered porous plate (the porous with HDPE inner plate) in the blowing

system plugged configuration was O.OO85f 0.0004. This resulted in a 7.6% increase in the drag. It was concluded that the porous plate with an HDPE inner plate is a good MBT skin because the drag increase due to the holes was less than 10%. Drag reduction wao observed for blower settings of 05, 08, 10 and 15. A slight anomaly occurred with blower setting 13, but this was al1 within the error range. Maximum drag reduction of 6% occurred with blower setting 05 which had a blowing parameter of 0.39 (kg / s /m2) .

This study was not a complete investigation of MBT's effect on the profile drag, but it has proven that Micro-blowing technique indeed reduces drag with the right blowing conditions. Many future tests are needed to fully investigate MBT's effect on total mode1

drag.

Chapter 6

Future Recommendat ions

For future work on MBT, 1 suggest the following:

1. Travening should be automated with the use of a controller which can communicate with the PC. This would reduce the time taken for one complete traverse.

2. A more controlled blowing system is needed. A compressed air supply with a mass

flow controller/meter should be used to control the mass flow more effectively.

Lower mass flows (or blowing parameter) cases c m also be investigated if this

system is installed.

3. An interesting setup would be to put some strips of aluminum tape over the porous

plate to create strips of porous regions.

4. Investigate using very thin porous plate with the HDPE inner plate. The thin

outer porous plate would not be drilled to make holes. It would be anodized with

chernical agents to make molecular size holes. This would Save substantially on the

cost of the porous plate (100 times less expensive).

References

[l] D .P. Hwang. "Skin-hctaon Reduction by a Micro-blocuing Technique. ", AIAA Jour- nal Vol. 36. No. 3,1998

[2] D .P. Hwang. "Skin- fiction Reduction by Micro- blowing Technique. ", Technical Re- port N96-22753, NASA, Dec. 1995.

[3] D.P. Hwang. (54 Proof-of-concept EzpeRment for Redvcing Skin fiction b y using Micro-Blowing Technique. ", AIAA Paper 97-0546, Jan. 1997.

[4] M . Drela. A User's Guide to MSES 2.8, MIT Computational Aerospace Sciences Laboratory, May 19%.

[5] H. Schlichting . "Boundary-Loyer Theory. ", 7th Edition, McGraw-Hill, Toronto, 1979, 758-767.

[6] "User's Guide: 8300 Series Stepping Motor Controller/Drivers", Velmex Inc., New York, Jan. 1985.

[7] "User 's Manual: BTI- 8UO/815", Analog Devices, 1990.

Appendix A

Data Tables

A.1 Solid Plate Traverses: Baseline Drag

Table A.4: BDSOLIDB: Solid Plate Traverse 2 Integrand Summary

For wake of YP3S.00 la Vd20.00 Dmg = 0.0074

Table A.6: BDSOLID3: Solid Plate Traverse 3 Integrand Summary

A.2 Porous Plate Traverses

Data from porous plate traverses without HDPE inner badtings are presented here.

Water filter on.

No HDPE inner plate. Porow plate on.

Table A. 12: P04WUNPLUG: Integrand of Porous Plate naverse with Unplugged Pipe

Run D.rulpUon: 901BS05 Ps measured uEhg MPX4115AP

Table A.14: P04BS05: Run Data of Porous Plate naverse with Blower Setting of 05

For wake 01 Y 2 5 0 0 to Y320.00 Drag betm bbwing m v e d = 0.0129

Table A.15: P04BS05: Integrand of Porous Plate naverse with Blower Setting of 05

Run Dncrlptbn: Dale: Sept. 0% 1998 Ps rneasured ushg MPX4115AP ~unnel vdody 4 6 m 6 4 mh lb1.690~394 ws

15T1476

Table A.17: P04BS08: Run Data of Porous Plate naverse with Blower Setting of 08

For wake of Y S. 00 to YdO. 00 Orag M o r e bbmng term retnoved = 0.0129

Table A.18: P04BS08: Integrand of Porous Plate 'Praverse with Blower Setting of OB

Run 1 YIC 1 O(-) 1 P. -(P.)

3 1 0.7066421 1286.520267I 96674.689868 32 1 0.4037361 1276.~~07ll1 96684.496568

For wake of Y-35.00 to Y40.W D r a ~ before biowing t m m v s d - 0.01 23

Table A.21: P04BS10: Integrand of Porous Plate naverse with Blower Setting of 10

A.3 Porous Plate with HDPE Inner Plate On

Data from porous plate traverses with HDPE inner backings are presented here.

Water filter on. HDPE inner plate on.

Porow plate on.

Run [krcription: WHWBSOO M e : Oct 16,1998 Tunnel Fan Setling: +W, Bkwer !Ming: 00 TumiVebd(y 47 10338281 (rnk) 154 7354423 m) Water Filer On, HDPE lnner Plate On Rbymüs Nunbw 1609140

Table A.25: W104BS00: Run Data of Porous Plate naverse with Blower Setting of 00

Run M p U o n : mOIBSOO Tunnel fan Seîîlng: +04, Blainer Setting: 00 Waler Fller On, HOPE lnner Plate On

47 16336281 (mh) 154 -3 (((VI)

1609140

Table A.27: WI04BS00: Massflow of Porous Plate naverse with BIower Setting of 00

Run bscrlptlon: m 0 4 8 5 û S ûab: Ocî. 09,1998 Tunnel Fan Sening: +W, Bbwer W h g : 05 Tund vsbay 47.73mus28 (n~.) lm 61 701 21 (a) Watw filier on, HDPE imer plate on, fleymids Numkr 1628'107

Table A.28: W104BS05: Run Data of Porous Plate naverse witb Blower Setting of 05

Rur, Chctiptiœl: wlo4Bsls Tunnel Fan Ming: +M. Blower Setting: 05 Water fiher on, HDPE inner phle on,

Table A.29: W104BS05: Integrand of Porous Plate Traverse with Blower Setting of 05

Run thscription: W1048S05 Tunnel Fan Setbjng: 44, Bbwer Setting: 05 Watei l ter on, HDPE imer phle on,

~ ~ ( i n . ) 1 A. (ma) I &(ml) 1 a n f ( ~ i ) 1 wnf ( ~ a ) I b 1 t

1 593750001 0001287061 0 0 0 1 7 ~ 13Q648U31 47-1 O 10161 0 4953

Table A.30: WI04BS05: Massflow of Porous Plate 'Iiaverse with Blower Setting of 05

Run br#lpUon: W104BSOB ht.: Ott. 09.1098

Tunnel Fan Selting: +04. Bbwer Setting: OB Tunml V o w i 4s 81766873 (-1 153 go12754 (Râ) Waler iller on, HDPE inner phle on, Reynoids ~unbei 1597346

Table A.31: WI04BSO8: Run Data of Porous Plate naverse with Blower Setting of OB

Run 0.rcilpUon: WID48S08 Tunnel Fan W n g : +W, Bbwer SetMg: 08 Wder Mer on, HDPE innec plate on,

O*: Oct. 09,1998 Tunnel Vsbcty R e y d d s Numbsr

BSûô, Tunnel On l.71216û APm 0.0068M

Table A.33: WI04BS08: Massflow of Porous Plate naverse with Blower Setting of 08

Run bsuiption: M S 1 0 Rib: Ott. 09,1998 Tunnel Fan Setting: +W, Bbwer Sening: 10 Tund Vabuy 4a.saui2711 (mk) 152.7891178 (W.) Water filter on, HDPE kner plate on, ~ o p l d s NU*I 1 Mm92

Table A.34: WI04BS10: Run Data of Porous Plate naverse with Blower Setting of 10

Run Description: WYIQBS10 bts. ûct. OQ, 1998 Tunnel Fan Setting: +04, Blow= Setting: 10 Tunnel Vebcity 46.S4ûZ7ll (nJi) 152.769ll78 (Rb) Water filer on, HDPE inner plate on, f l e y n o ~ s ~umbet 1 w s z

Table A.35: W104BS10: Integrand of Porous Plate naverse with Blower Setting of 10

Run ûo8crim: WIWBSlO Tunnei Fan Setting: 4, BWer Selng: 10 Water fiiîer on, HDPE inner plate on,

[hW. oct 09,1998 Tunnol VV.bdy

Reynoldr Nu-

Table A.36: WI04BS10: Massflow of Porous Plate Traverse with Blower Setting of 10

Run Description; WüMBS13 DeW. k t . 10,1990 Tunnel Fan Selling: +04, Bbwer Setting: 13 Tunnel voioclty 4s.atrs91u7 (m) 153.me3021 (Rh) Wabr Wr on, HOPE imer phle on, Rayndds Nunbor 1 ~ 1 ~ 9 ~ 1 1

Table A.37: W104BS13: Run Data of Porous Plate naverse with Blower Setting of 13

Run Description: WiW8S13 Date: ûct 10,1998 Tunnel Fan SMhg: +04, Blower Seîting: 13 Tunnel Vdocity

Watw filter on, HDPE inner plale on, Rsynob ~urnbsi

Table A.38: WI04BS13: Integand of Porous Plate maverse with Blower Setting of 13

Run Dimcrlptlon: WîMBS1S Dab: Oct 16,1998 Tunnel Fan Setting: +04, Wower SeMing: 15 rm J vebaty 47 76011666 (mk) 156 6932958 (tv.) Water fiiter on, HDPE inner plate on, lb jnokb ~irrki 1 6 ~ ~ 5 0 1

Table A.40: WI04BS15: Run Data of Porous Plate 'haverse with Blower Setting of 15

Run ûe8crlptlon: WiiMBS15 Tunnel Fan Setting: 44, Blowef Setting: 15 Water fiiîer on, HDPE Lnner plate on,

Date: Oct 16,199B Tunrml V . W

Reynolds Nu-

Table A.42: WI04BS15: Massflow of Porous Plate Traverse with Blower Setting of 15

Porous Plate with HDPE lnner Plate On

Table A.43: Summary of Profile Drags

Appendix B

Profile generation program: Efoi1.c

/* f1at fo i l . c -- calculates the f latfoi l profile.

Leading Edge : Ellipse Main Section : Flat

Trailing Edge: Parabolic vith slope control

programmed by Nam Suk Choi 1997 */

#inchde Cstdio.h> #inchde <stdlib.h> #include <math.h>

#define CHORD 46.72

#def ine TOTALPTS 100

#define LEAD 50

#define MAINPTS 5

#def ine TRAIL 45 #define XLEAD 11.2014

#define WTGT 1.6002

#def ine XTRAIL 14.1986

#def ine THETAS 180

#def ine THETAE 90

Xdef ine P I 3.141592

M e f ine OüTFILE "elipf o i l . ryil

/* 1 . 5 feet */

/* 4.41 inchee (major aria)*/ /* 0.63 inches (minor axis) */

int main(void)

C FILE *profile,*nprofile,*profile2;

double coord [TOTALPTS] [2] ;

double Xinit,delx,delt,ARe,Xnext,XafterTF;

double x,z,xnorm,znorm;

double dtheta,thS,thE,px,py,nt,ry,qx,qy;

int i,tpts;

tpts = LEAD+MAIWPTS+TRAIL;

if ( (prof i l e= f open(0üTFILE. " w ~ ~ ) ) == NUU)

C fprintf (stdin ,"Can8t open 1 s file. \nW ,OUTFILE) ; e x i t (1) ;

1 nprof ile = f open( "enrmfoil . xy" , Wt) ;

/* Calculate leading edge front section */ thS = THETAS*(PI/l80.0) ;

thE = THETAE* (PI/l8O -0) ;

dtheta = (thE-thSI/ (LEAD-1) ;

for (i=O ; i<=LEAD- 1; i++)

C x = XLEAD*cos(thS+(dtheta*i));

x = x + XLEAD; z = ZHGT*sin(thS+ (dtheta*i) ) ;

xnorm = x/CHORD;

znorm = z/CHORD;

coordhj 111 =xnorm; coord Ci] 121 = m o n ; if (1==1)

printf ("X is %f \nu, x) ;

CHAPTER B. PROFILE GENERATION PROGRAM: EFOIL.C

fprintf(profi1e. g1%1S.7f

fprintf (nprof i l e , "X16.7f if (i==LEAD-1)

Xnext = x;

1 printf ("X after the

ge tch0 ; /* Calculate Main S

leading

ec t ion c

edge i a %f \nt' , Xnext ) ;

oordinates */

f or (i-1; i<=MAINPTS-1; i++)

x = Xnext + (delx * i ) ;

z = ZHGT;

xnorm = x/CHORD;

znorm = z/CHORD;

coord [LEADti] [il =xnom;

coord [LEADti] [2] =znorm ;

fprintf (prof i l e , "%15. 7f %15.7f \nq' ,x ,z) ;

f printf (nprof i l e , Ib%15.7f %15.7f \ni' ,xnorm, znorm) ;

i f (i==MAINPTS-1)

Xnext = x;

1 printf ("X af ter the main sec t ion is %f \n" ,Xnext) ;

getcho ;

/* Calculation of the t r a i l i n g edge sect ion */ de l t = ( 1 . O / (TRAIL-1) ) ;

px = Xnext;

py = ZHGT; rx = Xriext+((CHORD-Xnext)/2.0) ;

ry = WGT; qx = CHORD;

qy = 0.000;

CHAPTER B. PROFILE GENERATION PROGRAM: EFOIL.C

for(i=O;i<=TRAIL-i;i++)

x = (qx-2 .O*rx+px)*(delt*i)*(delt*i)+2.O*(rx-px)*(delt*i)+px;

z = (qy-2.O*ry+py)* (delt*i) *(delt*i) +2. O* (ry-py) *(delt*i)+py ;

xnorm = x/CHORD; znorm = z/CHORD;

coord [LEAD+MAIWPTS-i+i] [il =xnorm; coord [LEAD+MAINPTS-l+i] 121 =znorm; fprintf(profi1eD"%16.7f %1S.7f\nn,x,z);

fprintf (nprof ile . "%15.7f #iS -7f \nt' , xnom, 2110m) ;

printf(ItX: Xf Y: %f\n4',x,z);

if (i==TRAIL-1)

Xnext = x;

3 printf (I1Xaf ter Trailing edge is %f \nu Jnaxt) ;

getch0 ;

prof ile2.f open(I1ef oilall . xy" . "vN) ;

for (i=tpts-2 ; i > = O ; i--)

fprintf (prof ile2, 11%15. 7f %15.7f \nt', coord [il [il , -coord [il [2] ) ;

for (i=l;i<=tpts-2;i++)

fprintf (prof ile2. I1%15.7f x15.7f \nt', coord [il Cl] , coord[i] C23 ) ;

f close (prof il021 ;

f close (nprof ile) ;

f close (profile) ;

return 0 ;

1

Appendix C

Porous Plate Calculat ion Program:

/* Porous Plate Hole Arrangement Calculation Progam */ /* March 24, 1997 by Nam Suk Choi */

#define MYFILE "POR,O6.AR5" #define POROSITY 0.23

#def ine AR 5

#def ine LENGTH 8 .O

#def ine WIDTH 4 .0

tdef ine THICKNESS 0.06

tdef ine P I 3.14159265369

#def ine INCHTOMM 25.4

#def ice SQINTOMM 645.16

int main(void1

C FILE *fp;

double Aholes, Aonehole; double Dhole , TotalArea;

double SideRat i o , uspace , lspace ;

double TotalHoles, rouN, coi!¶;

f p=f open (MYFILE, llv+l') ;

Dhole = THICKNESS/AR;

Aonehole = (PI*Dhole*Dhole) /4;

TotalArea = LENGTH*WIDTH;

Aholes = TotalArea*POROSITY;

TotalHoles = Aholes/Aonehole;

SideRatio = LENGTH/WIDTH;

/* Find number of holee per l i n e */

rovN = sqrt ( (TotalHoles*WIDTH) /LENOTH) ; colM = ~ovN*SideRatio;

/* colM = TotalHoles/rouN; */ /* Find the spacing of the holes i n a rou

and columnwise. */

wspace = (WIDTH -(rovN*Dhole) ) /(rovN-1) ;

lspace = (LENGTII -(colM*Dhole)) /(coUI-i) ;

/* Output Results */

f p r i n t f ( f p , " THE POROUS PLATE HOLE ARRANGEMENT CALCUUTED USING

\"PORPLATE.C\" \nN);

fp r in t f ( fp , \nu) ;

fpr in t f ( fp , I1 LENGTH: X10.2f INCHES.%c WIDTH: %10.2f INCHES \n",

LENGTH,' ',WIDTH);

fp r in t f ( fp , TOTAL AREA OF THE PLATE: X15.5f SQ . INCHES. \n" ,TotalArea) ;

fp r in t f ( fp , '@ %5.2f ./A of the TOTAL AR&A is X15.5f SQ . INCHES. \n1I.

POROSI~*100, Aholes) ;

fp r in t f (f p , l1 ASPECT RATIO (T/D) : %5d \na' ,AR) ;

fp r in t f ( fp , " PLATE THICHNESS : X15.5f INCHES. \nl' .THICKNESS) ;

fprintf (fp. DIAMETER OF EACH HOLE: X15.5f INCHES. \dl .Dhole) ; fprintf(fpD8' AREA OF ONE HOLE : %15.5F SQ . INCHES. \nN , Aonehole) ; fprintf(fp." TOTAL NUMBER OF HOLES WQüIRED: X10.2f HOLES.\n",TotalHoles); fprintf(fpBU TOTAL NUMBEA OF HOLES PWI ROW : %10.2f HOLES.\nlt,rovN);

fprintf (fp,I1 TOTAL NUMBER OF HOLES PER COL : % I O .2f HOLES. \nt', colM) ;

fprintf (fp. " SIDE RATIO: %IO. Sf \n8', SideRatio) ; fprintf (fp , SPACING BETWEEN EACH HOLE IN A ROW: XIE. 5E INCHES. \n'ID uspace) ;

fprintf(fpSo1 SPACING BETWEEN EACH ROW IS : %1S. 5E INCHES. \nt', lspace) ;

fprintf(fpB8I \na');

f printf (fp , ** SPACINGS ARE MEASURED HOLE EDGE-TO-HOLE EDGE NOT FROM\nm') ; fprintf (fp , THE HOLE CENTER TO HOLE CENTER. \nu) ;

f close (f p) ; printf ("DONE SAVING OUTPUT TO \" %s \" \nl',MYFILE) ;

1

EXAMPLE OUTPUT 1

THE POROUS PLATE HOLE ARRANGEMENT CALCULATED USING "P0RPLATE.C"

LENGTH : 8.00 INCHES, WIDTH: 4.00 INCHES

TOTAL AREA OP THE PLATE: 32.00000 SQ. INCHES.

23.00% of the TOTAL AREA is 7.36000 SQ. INCHES.

ASPECT RATIO (T/D) : 4

PLATE THICHNESS : 0.06000 INCHES.

DIAMETER OF EACH HOLE: 0.01500 INCHES.

AREA OF ONE HOLE . 1.76715E-004 SQ. INCHES.

TOTAL NUMBER OF HOLES REQUIRED: 41649.08 HOLES.

TOTAL NUMBER OF HOLES PER ROW : 144.31 HOLES.

TOTAL WUMBER OF HOLES PER COL : 288.61 HOLES.

SIDE RATIO: 2.00000

SPACING BETWEEN EACH HOLE IN A ROW: 1.28074E-002 INCHES.

SPACING BETWEEN EACH ROW IS P 1.276293-002 INCHES.

** SPACINGS ARE MEASURED HOLE EDGE-TO-HOU EDGE NOT FROM THE HOLE CENTER TO HOLE CENTER.

EXAMPLE OUTPUT 2

TNE POROUS PLATE HOLE ARRANGPiENT CRLCULATED USING "PORPLATE .CM

LENGTH : 8.00 INCHES, WIDTH: 4.00 INCHES

TOTAL AREA OF THE PLATE: 32.00000 SQ. INCHES. 23.00% of the TOTAL AREA is 7.36000 SQ. INCHES.

ASPECT RATIO (T/D) : 5

PLATE TH1 CHNESS : 0.06000 INCHES.

DIWER OF EACH HOLE: 0.01200 INCHES.

AREA OF ONE HOLE 1.13097E-004 SQ. INCHES. TOTAL NUMBER OF HOLES REQUIRED: 65076.69 HOLES.

TOTAL NüMBER OF HOLES PER ROW : 180.38 HOLES.

TOTAL NUMBER OF HOLES PER COL : 360.77 HOLES.

SIDE RATIO: 2.00000

SPACING BETWEEN EACH HOLE IN A ROW: 1.02317E-002 INCHES.

SFACING BETWEEN EACH ROW IS . 1.02032E-002 INCHES.

** SPACINGS ARE MEASURED HOLE EDCE-TO-HOLE EDGE NOT FROM

THE HOLE CENTER TO HOLE CENTER.

Appendix D

Data Acquisition Program: Fourchs. bas

>This program is written for the wake traverse manual mode.

a INPUT "Y LOCATION ? I I , nom OPEN "O", #1, "OUT. DAT"

PIOBASE = Mi300 RTIBASE = &H310

CHADD = PIOBASE + 1: UPDATE = PIOBASE + 2: CNTL = PIOBASE + 3

STARTCONV = RTIBASE + 2: HIGH = RTIBASE + 4: LOW = RTIBASE + 3

OUT RTIBASE, O

OUT CTRL, 128

OUT UPDATE, 1

' INPUT "NUMBER OF SCANS ? l ' , SCANUM P R I N T lI================r============~=====~============='l

P R I N T "SCANNING 100 TIMES . . ." SCANUEi = 100

DIM VOLTS(4, SCANUM)

SUM(1) = O!: SUM(2) = O!: SUM(3) = O!: SUM(4) = O !

FOR 1 = 1 TO SCANüM

FOR J = 1 TO 4 J,,,,,,,,, READ START A/D CONVERSION AND READ DATA ---------

CH = J

OUT RTIBASE + 1, CH SELECT CHANNEL AND GAIN

OUT STARTCONV, O START A/D CONVERSION

FOR X = O TO 50: MUT X ' DELAY BEFORE READING ADC DATA

HIEYTE = IHP(H1GH): LOBYTE = INP(L0W) 'READ A/D CONVERTER DATA

COUNT(CH) = 256 * HIBYTE + LOBYTE

VOLTSCJ, 1) = (COUNT(CH) / 4095) * 1 0 !

'PRINT CH, COUNT(CH) , VOLTS(J, 1)

SUM(J) = SUM(J) + VOLTS(& 1)

NEXT J

NEXT I

FOR K = 1 TO SCANUM PRINT #1, K , VOLTS(1, K) , VOLTS(2, K) , VOLTS (3, KI, VOLTS(4, K)

NUiT K FOR L = 1 TO 4

AVG(L) = SUM(L) / SCANUM

PR1 NT "AVG VOLTAGE ON CH", L, : " , AVG(L)

NEXT L

PRINT tl, 1000, A V G ( I ) , AVG(2), AVG(3). AVG(4)

CLOSE #1

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