EXPERIMENT 3Flow Over WeirExperimental date: 19 Jan 2015Due Date: 20 April 2015NameID

Sayed Ali JourabchiI14006420

Bryan MatthewrajI13004120

SurinkumarI13004113

Leonard TanI11008508

Table of ContentDescriptionPage no.

Hypothesis and Objective3

Introduction4

Apparatus5

Procedures6

Results7-8

Discussion9

Conclusion10

References11

HypothesisBy a utilization of the Bernoulli equation the outcomes for stream over weirs can be acquired. The profundity of stream over the base of an indent is identified with the volume stream rate through it; the score structures a helpful flow measurement device.ObjectiveThis experiment is conducted in order to achieve the following objectives:(a) To analyse flow characteristics over a rectangular notch.(b) To analyse flow characteristics over a V- notch.(Part 2)

IntroductionIn open channel hydraulics, weirs are normally used to either control or to quantify the volumetric flow rate. They are of specific use in expansive scale circumstances, for example, watering system plans, trenches and streams. For small scale applications, weirs are regularly alluded to as notches and invariably are sharp edged and produced from dainty plate material. The estimation of water streaming in open diverts is critical in numerous parts of our general public. For instance, water streaming in waterways and streams must be checked to guarantee satisfactory water supplies for private and modern employments. In farming, water is frequently passed on to agriculturists in open channels for inundating fields, and such designations are strictly controlled. It is additionally imperative to quantify water stream amid flooding occasions for water level expectation with a specific end goal to stay away from property harm and death toll. Most techniques for measuring water stream in open channels include putting a "block" in the channel that reaches out from one channel limit to the next. Water goes down and after that overflow or through the obstacle. Substantial hindrances, which are fit for measuring open direct stream in streams, are called dams1. In littler streams and trenches we utilize weirs to quantify water stream, which are littler and all the more basically basic. Weirs are the most widely recognized system for measuring streams in open channels, and they are generally connected in both the field and the research facility. They will be the center of today's research facility test.

Apparatus: This experiment was carried out using the Flow over Weir Apparatus.

Figure 1.0: Flow over Weir Apparatus Figure 1.2:Figure 1.1: Part 2Part 1

Procedure:Part 11. The hydraulic bench was ensured to be located on a levelled floor as the accuracy of the results will be affected if the bench top is not levelled. The equipment was set up as shown in the diagram.2. The Vernier Height Gauge was set to a datum reading by placing the point on the crest of the weir. The weir plate with the point gauge was not damaged as it was taken with extreme care.3. The gauge was positioned about half way between the notch plate and stilling baffle. Water was poured to the channel, flow control valve was adjusted to obtain heads, H increased in steps of about 1 cm. For each flow rate, the conditions were stabilized, H was measured and recorded. The readings and volume and time used the volumetric tank to determine the flow rate was taken down.Part 21. The hydraulic bench was ensured to be located on a levelled floor as the accuracy of the results will be affected if the bench top is not levelled. The equipment was set up as shown in the diagram.2. The Vernier Height Gauge was set to a datum reading by placing the point at the bottom of the V-notch on the weir .The weir plate with the point gauge was not damaged as it was taken with extreme care.3. The gauge was positioned about half way between the notch plate and stilling baffle. Water was poured to the channel, flow control valve was adjusted to obtain heads, H increased in steps of about 1 cm. For each flow rate, the conditions were stabilized, H was measured and recorded. The readings and volume and time used the volumetric tank to determine the flow rate was taken do

Results and calculationPart 1: Rectangular notchH (mm)Volume ()Time (sec)Q ()Log HLog Q

4912235x5x5x5x119754.545x5.556x

7.143x1x2.530x 8.538x1.315x3.488x-2.380-2.046-1.920-1.638-3.342-3.255-3.146-3.000

Table 1.0

Formula**Calculation:1.) Q = Q = = 4.545x2.) = = 2.530x 3.) = Log (4x) = -2.3804.) = Log (4.545x) = -3.3425.) = =

Part 2: V-notchH (mm)Volume ()Time (sec)Q ()Log HLog Q

222332385x5x5x5x754620136.667x1.087x

2.5x3.846x7.179x8.023x1.832x2.815x-1.658-1.638-1.495-1.420-4.176-3.964-3.602-3.4150.39310.57355.7775.783

Table 1.1

Formula**Calculation:1.) Q = Q = = 6.667x2.) = = 3.) = Log (4) = 0.60214.) = Log (4.545x) = -3.3425.) = = 0.3931

Discussion The Discharge coefficient for both the rectangular notch and the V-notch get to be more precise to the hypothetical quality when the flow rate increments. This is because of the way that when the stream rate is bigger the stream ventures from the notch and it doesn't stick to the notch. At the point when the water sticks to the score the exactness of the flow rate diminishes. Additionally the lower stream rates produce lower statures over the indent making bigger changes from the hypothetical theoretical equations.

Figure 1.3

During the experiment, a smooth flow of the fluid was favoured before measuring the head on weir. It was due to the assumption that the distribution of velocities in approach flow has a definite influence on the discharge over the weir. As the valve loosened the head increased. This increase resulted in the change of the fluid flow.

ConclusionAfter conducting all two parts of this experiment using the Flow over Weir Apparatus, we have successfully obtained the necessary information to investigate the flow characteristic for the rectangular notch and V-notch. As the stream rate builds the release coefficient gets to be more precise to the hypothetical quality. At the point when the stream rate is to low it sticks to the score and streams down it. These progressions the coefficient of release in light of the fact that now the water isn't just being influenced by gravity it needs to oppose the grating of the surface of the score. The limits of the hypothesis is it must be level so the main constrain on the water is gravity, there must be a steady stream, and consistent weight. The hypothesis behind this examination makes a suspicion that there is a base tallness of water over the indent and any statures beneath this begin to go amiss from hypothesis at an expanding rate. The lower stream rates produce lower statures over the score making bigger changes from the hypothetical mathematical statements. The smooth stream to and over the weir is vital to the determination of exact rates of stream following the circulation of speeds in the methodology stream has an unmistakable impact on the release over the weir. It was likewise noticed that the head influences the stream of water. The relationship between the leader of the weir and the release of the water over the weir is specifically proportional. Aside from the speed and the head, the varieties in these liquid properties assistant will impact the release over the weir. There are some experimental error that occur during this experiment that disrupt the readings. There are many factors that contribute to the reliability of the experiment and can be a cause of possible errors, below is a list of a few factors that were taken to mind:Human errorSpeed of the flow rateExperimental repeatability

Reference 1) http://site.iugaza.edu.ps/mymousa/files/Experiment-6-hydraulics-lab-.pdf2) http://johnefuller.weebly.com/uploads/1/7/8/7/17878951/flow_over_weirs.pdf

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