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VALIDATION A TWO-PHASE NUMERICAL

SOLVER FOR SIMULATING HYDRAULIC BORE

INTERACTIONS WITH NEARSHORE

STRUCTURES

7TH International Tsunami Symposium

ISPRA 2016

Steven Douglas

Academic Supervisor: Dr. Ioan Nistor

September 12 - 15th, 2016

2Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures

PRESENTATION OVERVIEW

PRESENTATION OVERVIEW

Introduction

Objectives

The Numerical Model

Results

Conclusions

RISK MITIGATION

PUBLIC

AWARENESS AND

EMERGENCY

PREPAREDNESS

Inundation maps

Early warning systems

Evacuation plans

STRATEGIC

MITIGATION

Land-use planning

Soft engineering

Hard engineering/Building codes

INTRODUCTION : MITIGATION OF TSUNAMI EFFECTS

INTRODUCTION: MITIGATION OF TSUNAMI EFFECTS

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Deficiencies in existing design guidelines:

• Ghobara et al. (2006) • Nistor et al. (2009)• Chock et al. (2011)• Yeh et al. (2013)

“A comprehensive update of tsunami provisions has not beenmade largely due to lack of adequate data” – Chock et al.(2011)

Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures

The Cascadia Subduction Zone

[The Camino, 2007]

4

STUDY OBJECTIVES

STUDY OBJECTIVES

Short-term goals

• Provide analysis of the hydrodynamic loading process

• Investigate role of entrained-air in loading process

• Comparative analysis with SPH

• Validate recent tsunami design guidelines

• FEMA P646

• ASCE 7-16

• Investigate influence of flume geometry

• Investigate influence of bed condition (ℎ𝑑)


Reproduction of physical experiments (Al-Faesly et al., 2012) using a two-phase numerical model

Long-term goals

• Aid in the advancement of tsunami design guidelines

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THE NUMERICAL MODEL : INTERFOAM

THE NUMERICAL MODEL: INTERFOAM

Numerical details:• Two incompressible fluids (air/water)• Volume of fluid (VoF)• Reynolds-averaged with turbulence• Artificial interface compression• Dynamic time step• Finite volume discretization

𝜕𝛼

𝜕𝑡+ 𝛻 ∙ 𝐔𝛼 + 𝛻 ∙ 𝐔𝐜𝛼 1 − 𝛼 = 0

Phase fraction (𝛼)

𝜕𝜌𝐔

𝜕𝑡+ 𝛻 ∙ 𝜌𝐔𝐔 = −𝛻𝑝∗ + 𝛻 ∙ 𝜇𝑒𝑓𝑓𝛻𝐔 + 𝛻𝐔 ∙ 𝛻𝜇𝑒𝑓𝑓 − 𝒈 ∙ 𝒙𝛻𝜌 + 𝜎𝜅𝛻𝛼

𝛻 ∙ 𝐔 = 0 Conservation of massConservation of momentum

Transport equation for phase fraction

AIR

WATER


BORE-STRUCTURE INTERACTION: PHYSICAL EXPERIMENTS

(AL-FAESLY ET AL., 2012)

THE PHYSICAL EXPERIMENTS (AL-FAESLY ET AL., 2012)

WAVE GAUGES

• w/ structure

• w/out structure

Experimental data• 8 wave gauge (WG)• 10 pressure transducers (PT)• 1 6-DOF force gauge

Experimental setup• Unobstructed flow• Obstructed flow w/ square • Three ℎ𝑢:

• 0.55 m• 0.85 m• 1.15 m


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CALIBRATION OF NUMERICAL PARAMETERS

𝒉𝒖 (m)Computational

Mesh

No. Grid

Cells

Computational

Time

0.85 5x5x5 169,735 2.6 hours

0.85 3x3x3 785,809 9.47 hours

0.85 2x2x2 3,608,180 1.62 days

0.85 1.5x1.5x1.5 8,468,152 3.79 days

0.85 2x2x2 Refined 1 5,496,080 3.04 days

0.85 2x2x2 Refined 0.5 8,703,596 8.86 days

1.15 2x2x2 Refined 1 7,025,110 5.63 days

1.15 2x2x2 Refined 0.5 10,176,435 >20 days


MeshTurbulence Model

Computational

Time

0.85 2x2x2 Refined 1 𝑘 − 𝜖 3.04 days

0.85 2x2x2 Refined 1 RNG 𝑘 − 𝜖 3.97 days

0.85 2x2x2 Refined 1 𝑘 − 𝜔 SST 3.40 days

1.15 2x2x2 Refined 1 𝒌 − 𝝐 5.63 days

1.15 2x2x2 Refined 1 RNG 𝑘 − 𝜖 6.65 days

1.15 2x2x2 Refined 1 𝑘 − 𝜔 SST 5.91 days

1.15 2x2x2 Refined 1 Realizable 𝑘 − 𝜖 5.72 days

CALIBRATION OF NUMERICAL MODEL Mesh size


Mesh𝑪𝒐𝒎𝒂𝒙

Computational

Time

0.55 2x2x2 Refined 1 0.8 0.95 days

0.55 2x2x2 Refined 1 1.0 1.18 days

0.55 2x2x2 Refined 1 2.0 1.75 days

Mesh size calibration

Turbulence model calibration

Maximum Courant Number calibration


VIDEO: NUMERICAL SIMULATION, ℎ𝑢=1.15m, SQUARE STRUCTURE


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MODEL VALIDATION: UNOBSTRUCTED FLOW

TIME: 0.75 SEC

TIME: 1.0 SEC

TIME: 1.25 SEC

MODEL VALIDATION: BORE PROFILES AND WATER LEVELS


10Numerical Modeling of Extreme Hydrodynamic Loading and Pneumatic Long Wave Generation

DEVELOPMENT OF PRESSURES AND FORCES

TIME: 1.05 secTIME: 1.9 secTIME: 2.35 secTIME: 3.6 secTIME: 7.0 sec

Impulsive ForcePeak SplashCollapse ForcePeak Hydrodynamic ForcePost-Peak Hydrodynamic

EXPERIMENTAL

NUMERICAL

Force t-history

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COMPARISON OF NUMERICAL AND EXPERIMENTAL RESULTS

COMPARISON TO EXP. AND SPH RESULTS: FORCE TIME-HISTORY

ℎ𝑢 = 0.55 m

ℎ𝑢 = 1.15 m

ℎ𝑢 = 0.85 m

• Better agreement as ℎ𝑢(impulsive and hydrodynamic)

• Runup collapse force overestimated as ℎ𝑢(incompressible air)


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INFLUENCE OF BED CONDITION

Influence of ℎ𝑑:• ℎ𝑑 = 0mm• ℎ𝑑 = 5mm• ℎ𝑑 = 20mm• ℎ𝑑 = 50mm


As ℎ𝑑 increases:• Reduction in bore-front celerity• Increase in bore-front depth• Change in impulsive and hydrodynamic load

FORCE TIME-HISTORY

BORE PROFILES

ℎ𝑑 = 0mmTIME: 1.35 seconds



Compressibility of air seems to have little to no dampening effect of the experimental impulsive load.

Compressibility of air has substantial influence on the magnitude of the collapse force.

Both InterFoam and SPH performed well to reproduce the physical interactions between the bore and structure. Alternative to SPH Riemann solver for controlling instabilities

Impulsive load can be the governing load for structures or structural components less than or equal to the bore-front depth. Not yet accounted for in existing or upcoming tsunami design guidelines

Good agreement observed between Chanson’s (2009) analytical and numerical bore profile.

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CONCLUSIONS

CONCLUDING REMARKS


QUESTIONS AND ANSWERS

THANK YOU!

QUESTIONS?

[REUTERS KYODO, 2011]


ARTICLES SUBMITTED TO REFEREED JOURNALS

[1] Douglas, S. and Nistor, I. (2014). On the effect of bed condition on the development of tsunami-induced loading on structures using OpenFOAM. Journal of Natural Hazards, 76, 1335-1356. DOI 10.1007/s11069-014-1552-2. (M.A.Sc. work).

ARTICLES SUBMITTED TO REFEREED CONFERENCE PROCEEDINGS

[3] Douglas, S., Nistor, I. and St-Germain, P. (2015). 3D multi-phase numerical modelling of tsunami-induced hydrodynamic loading on nearshore structures. 36th IAHR World Congress, The Hague, Netherlands, June 28 – July 3, 2015. (M.A.Sc. work).

[4] Douglas, S. and Nistor, I. (2016). Multiphase numerical model for predicting bore-induced loading on structures. 35th ICCE, Istanbul, Turkey, July 17 – July 22, 2016. (Abstract submitted September 29, 2015, Submission ID: 1267). (M.A.Sc. work).

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PUBLICATIONS

PUBLICATIONS


Al-Faesly, T., Palermo, D., Nistor, I. and Cornett, A. (2012). Experimental modeling of extreme hydrodynamic forces on structural models, International Journal of Protective Structures (IJPS), 3(4), 477-505.

Árnason, H. (2005). Interactions between an incident bore and a free-standing coastal structure. Doctoral dissertation, Univ. of Washington, Seattle, WA.

Chan, I. and Liu, P.L. (2012). On the runup of long waves on a plane beach. Journal of Geophysical Research, 117, 1-17.

Chanson, H. (2006). Tsunami surges on dry coastal plains: application of dam break equations, Coastal Engineering Journal, Japanese Society of Civil Engineers (JSCE), 48(4), 355-370.

Chanson, H. (2009). Application of the method of characteristics to the dam break wave problem. Journal of Hydraulic Research, 47 (1), 41-49.

Chinnarasri, C., Thanasisathit, N., Ruangrassamee, A., Weesakul, S. and Lukkunaprasit, P. (2013). The impact of tsunami-induced bores on buildings. Proceedings of the Institution of Civil Engineering (ICE), Maritime Engineering, 166, 14-24.

Chock, G., Carden, L., Robertson, I., Olsen, M., and Yu, G. (2013). Tohoku tsunami-induced building failure analysis with implications for U.S. tsunami and seismic design codes. Earthquake Spectra, 29(1), 99-126.

FEMA P646. (2012). Guidelines for design of structures for vertical evacuation from tsunamis. Federal Emergency Management Agency, Washington, D.C.

Ghobarah, A., Saatcioglu, M. and Nistor, I. (2006). The impact of the 26 December 2004 earthquake and tsunami on structures and infrastructure. Engineering Structures, 28 (2), 312-326.

Goseberg, N., Wurpts, A. and Schlurmass, T. (2013). Laboratory-scale generation of tsunami and long waves. Coastal Engineering, 79, 57-74.

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REFERENCES

REFERENCES


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REFERENCESLinton, D., Gupta, R., Cox, D., Lindt, J., Oshnack, M. and Clauson, M. (2013). Evaluation of tsunami loads on

wood-frame walls at full scale. J. Structural Engineering, 139 (8), 1318-1325.

Lukkunaprasit, P., Thanasisathit, N. and Yeh, H. (2009). Experimental verification of FEMA P646 tsunami loading. Journal of Disaster Research, 4(6), 410-418.

Nistor, I., Palermo, D., Nouri, Y., Murty, T. and Saatcioglu, M. (2009). Tsunami forces on structures. In Kim, Y. C., Handbook of Coastal and Ocean Engineering, World Scientific, pp. 261-286.

Nouri, Y., Nistor, I. and Palermo, D. (2010). Experimental investigation of tsunami impact on free standing structures, Coastal Engineering Journal, JSCE, 52(1), 43-70.

Ramsden, J.D. (1993). Tsunamis: forces on a vertical wall caused by long waves, bores, and surges on a dry bed. Ph.D. thesis, California Institute of Technology, Pasadena, California.

Robertson, I.N., Riggs, H.R., Paczkowski, K. and Mohamed, A. (2011). Tsunami bore forces on walls. 30th

International Conference on Ocean, Offshore and Arctic Engineering, Rotterdam, the Netherlands, June 19-24, 2011.

Rossetto, T., Allsop, W., Charvet, I., and Robinson, D.I. (2011). Physical modelling a tsunami using a new pneumatic wave generator. Coastal Engineering, 58, 517-527.

St-Germain, P., Nistor, I., Townsend, R. (2012) Numerical modeling of the impact with structures of tsunami bores propagating on dry and beds using the SPH method. International Journal of Protective Structures 3(2), 221–255.

Yeh, H., Sato, S. and Tajima, Y. (2013). The 11 March 2011 East Japan Earthquake and Tsunami: Tsunami effects on coastal infrastructure and buildings. Pure and Applied Geophysics, 170, 1019-1031.


REFERENCES

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Influence of ℎ𝑑:• ℎ𝑑 = 0mm• ℎ𝑑 = 5mm• ℎ𝑑 = 20mm• ℎ𝑑 = 50mm


As ℎ𝑑 increases:• Reduction in bore-front celerity• Increase in bore-front depth• Change in impulsive and hydrodynamic load

FORCE TIME-HISTORY

BORE PROFILES




DEVELOPMENT OF FORCES

FORCE

TIME-HISTORY

TIME: 1.05 sec

TIME: 1.9 sec

TIME: 2.35 sec

TIME: 3.6 sec

TIME: 7.0 sec

Impulsive

Collapse

Peak hydrodynamic


TIME-HISTORY OF VERTICAL PRESSURE DISTRIBUTION

PRESSURE: VERTICAL DISTRIBUTION

Leading edge

impacts column

Splash collapses

onto incoming flow

Peak hydrodynamic

forceWG9

Tends towards

hydrostatic pressure

TIME-HISTORY COLUMN RUNUP


21Numerical Modeling of Extreme Hydrodynamic Loading and Pneumatic Long Wave Generation

DEVELOPMENT OF PRESSURES AND FORCES

TIME: 1.05 secTIME: 1.9 secTIME: 2.35 secTIME: 3.6 secTIME: 7.0 sec

Impulsive ForcePeak SplashCollapse ForcePeak Hydrodynamic ForcePost-Peak Hydrodynamic

EXPERIMENTAL

NUMERICAL

22


CALIBRATION OF NUMERICAL MODEL: BORE-STRUCTURE INTERACTION

Wall functionTurbulence model

Mesh resolution

Max. Courant Number


kEpsilon kOmegaSST

RealizeableKE RNGkEpsilon



WAKE FORMATION [TIME: 2 seconds]


kEpsilon kOmegaSST

RealizeableKE RNGkEpsilon



WAKE FORMATION [TIME: 3 seconds]


(a) Time: 1.9 sec

(b) Time: 2.25 sec

(c) Time: 3.0 sec

(d) Time: 7.5 sec

EFFECT OF INTERFACE COMPRESSION

Interface compression on Interface compression off


(a) Time: 1.35 sec

(b) Time: 1.95 sec

(c) Time: 3.15 sec

(d) Time: 5.0 sec

EFFECT OF INTERFACE COMPRESSION

Interface compression on Interface compression off


27


COMPARISON TO EXPERIMENTAL RESULTS: WSE TIME-HISTORIES

WG1 WG9

WG11 WG13


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Pressure time-histories

(ℎ𝑢 = 1.15m)



FLOW SYMMETRY


Time: 3.5 sec

EFFECT OF CHANNEL WIDTH

WALL EFFECTS


Time: 3.5 sec


WALL EFFECTS


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