Determination of Coefficient of discharge for Rectangular and Triangular Notches | Flow over Notch

The coefficients of discharge are determined by measuring the height of the water surface above the notch base and the corresponding flow rate. The general features of the flow can be determined by direct observation.

The following equipment is required to perform the flow over weirs experiment:

F1-10 hydraulics bench;
F1-13 rectangular and triangular weirs;
Vernier height gauge; and
Stopwatch.

This experiment will be performed by taking the following steps:

Ensure that the hydraulics bench is positioned so that its surface is horizontal. This is necessary because the flow over the notch is driven by gravity.
Mount the rectangular notch plate onto the flow channel, and position the stilling baffle.
Turn on the pump, and slightly adjust the flow control to fill the channel upstream of the weir with water.
Turn off the pump when the water starts to flow over the weir.
Wait a few minutes to allow the water to settle.
Level the point gauge with the water level in the channel. Record the reading as ho.
Note: To measure the datum height of the base of the notch (ho), position the instrument carrier. Then carefully lower the gauge until the point is just above the notch base, and lock the coarse adjustment screw. Then, using the fine adjustment, adjust the gauge until the point just touches the water surface and take a reading, being careful not to damage the notch.

Adjust the point gauge to read 10 mm greater than the datum.
Record the reading as h.
Turn on the pump, and slightly adjust the flow until the water level coincides with the point gauge. Check that the level has stabilized before taking readings.
Measure the flow rate using the volumetric tank.
Observe the shape of the nappe and take pictures of it.
Note: The surface of the water will fall as it approaches the weir. This is particularly noticeable at high flow rates by high heads. To obtain an accurate measurement of the undisturbed water level above the crest of the weir, it is necessary to place the measuring gauge at a distance of at least three times the head above the weir.

Increase the flow by opening the bench regulating valve to set the heads above the datum level in 10 mm increments until the regulating valve is fully open. Take care not to allow spillage to occur over the plate top that is adjacent to the notch. At each condition, measure the flow rate and observe the shape of the nappe.
Note: To obtain a sufficiently accurate result, collect around 25 liters of water each time, or collect the water for at least 120 seconds.

Close the regulating valve, stop the pump, and then replace the weir with the V-notch.
Repeat the experiment with the V-notch weir plate, but with 5 mm increments in water surface elevation.
Collect seven head and discharge readings for each weir.

[samgamingshorts]

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[muhammadkhairulbasar]

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[tummariho]

Good work keep it up
6 done ✅💯✅ complete 💯✌️ Palwasha