Question

If the level of water (H) above the base point of V notch is increased by four times, the discharge through the notch will become s

• A. 4 times
• B. 8 times
• C. 16 times
• D. 32 times

Answer 1

Answer:

D. 32 times

Given: $H_{1} = H$ $H_{2} = 4H$

The discharge over a V-notch weir is given by the:

$Q = \frac {8}{15} C_d tan (\frac{\theta}{2})\sqrt{2g} H^{5/2}$

$\Rightarrow \frac{Q_1}{ Q_2} =(\frac {H_!}{H_2})^{5/2}$$\Rightarrow \frac{Q_1}{ Q_2} =(\frac {H}{4H})^{5/2}$$\Rightarrow \frac{Q_1}{ Q_2} =frac{1}{32}\Rightarrow Q_1=32$