Lab 3 - Flow Over Weirs.pdf

Lab 3 - Flow Over Weirs Allison Encarnacion Miguel Felix Adam Ahmadpour Donato Gonzalez California State University Long Beach CE 336 - Section 10 Loan Miller 9/22/2023

Purpose The purpose of this experiment was to examine how weirs can control the flow rate across a channel. Introduction A weir is a partial obstruction on a channel bottom over which fluid must flow. In this experiment a V-notch and a rectangular weir were used as their different geometric designs would lead to different flow rates. Our goal was to determine how each geometric design would affect the flow rate through the channel. The experiment started off with a rectangular weir. The hydraulic bench would automatically calculate the flow rate as the inflow rate was changed. When a steady flow rate was maintained, the height of the water and the flow rate were recorded. To avoid errors, the flow had to be steady before getting the data. The flow rate and height of the water level was taken for ten flow rates. The same process was repeated for the V-notch weir. Theory ? ? 𝛾 + 𝑧 ? + 𝑉 ? 2 2𝑔 = ? ? 𝛾 + 𝑧 ? + 𝑉 ? 2 2𝑔 𝐻 + ? 𝑤 + 𝑉 1 2 2𝑔 = 0 + (𝐻 + ? 𝑤 − ℎ) + ? 2 2 2𝑔 𝑢 2 = √2𝑔 (ℎ + 𝑉 1 2 2𝑔 ) ? 1 = ∫𝑢 2 𝑑𝐴 = ∫ 𝑢 2 ℎ=𝐻 ℎ=0 ℓ𝑑ℎ = ∫ 𝑢 2 ℎ=𝐻 ℎ=0 𝑏𝑑ℎ ? 1 = √2𝑔 𝑏 ∫ (ℎ + 𝑉 1 2 2𝑔 ) 1 2 𝐻 0 𝑑ℎ ? 1 = 2 3 √2𝑔 𝑏 [(𝐻 + 𝑉 1 2 2𝑔 ) 3 2 − (0 + 𝑉 1 2 2𝑔 ) 3 2 ]

? 1 = 2 3 √2𝑔 𝑏𝐻 3 2 ? 𝑎 = 𝐶 𝑑 ? 1 ? 𝑎𝑟 = 𝐶 𝑑𝑟 ? ?𝑟 = 𝐶 𝑑𝑟 2 3 √2𝑔 𝑏𝐻 3 2 𝐶 𝑑𝑟 = 0.611 + 0.075 ( 𝐻 ? 𝑤 ) ? 𝑎? = 𝐶 𝑑? ? ?? = 𝐶 𝑑? 8 15 √2𝑔 tan 𝜃 2 𝐻 5 2 Equipment

• locking and adjustment nuts • scale/ruler • weir carrier • instrument carrier • delivery nozzle • point gauge • V-notch weir wall • rectangular weir wall • flow-rate adjustment knob Discussion

Rectangle ℎ 𝑜 = 14.4 mm Flow Rate (L/s) h (mm) 1 0.097 24.5 2 0.179 32.1 3 0.257 38.2 4 0.336 43.2 5 0.415 48.3 6 0.495 53.1 7 0.575 57.4 8 0.655 61.4 9 0.735 65.5 10 0.815 69.1 Triangle ℎ 𝑜 = 15.7 mm Flow Rate (L/s) h (mm) 1 0.09 31.9 2 0.17 37.8 3 0.25 42.2 4 0.33 45.8 5 0.41 48.8 6 0.49 51.5 7 0.571 54.52 8 0.651 57.8 9 0.731 59.7 10 0.811 61.6 ? 𝑤 = 7.78 cm Table 3: Data Table for Rectangular Weir Weir Plate Height Datum H eight Water L evel Actual Flow Rate Height Above N otch Theoretical Flow rate Experimental Discharge Coefficient Theoretical Discharge Coefficient P w h o h Q H Q t C dr C dr ' m m m 𝑚 3 𝑠 ⁄ m 𝑚 3 𝑠 ⁄ unitless unitless 0.0778 0.0147 0.0245 0.000097 0.0098 0.0000859 1.13 0.62 0.0778 0.0147 0.0321 0.000179 0.0174 0.0002033 0.88 0.63 0.0778 0.0147 0.0382 0.000257 0.0235 0.0003191 0.81 0.63 0.0778 0.0147 0.0432 0.000336 0.0285 0.0004262 0.79 0.64 0.0778 0.0147 0.0483 0.000415 0.0336 0.0005456 0.76 0.64 0.0778 0.0147 0.0531 0.000495 0.0384 0.0006666 0.74 0.65 0.0778 0.0147 0.0574 0.000575 0.0427 0.0007817 0.74 0.65 0.0778 0.0147 0.0614 0.000655 0.0467 0.0008940 0.73 0.66 0.0778 0.0147 0.0655 0.000735 0.0508 0.0010143 0.72 0.66 0.0778 0.0147 0.0691 0.000815 0.0544 0.0011240 0.73 0.66 Table 4: Data Table for V-notch Weir

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help