Question

A 3-m wide rectangular channel has a flow velocity of 1.8 m/s when the depth of flow is 1.2 m. what will be the flow velocity when the depth of flow is increased to 3 m?

Answer 1

Answer:

The flow velocity reduces to 0.72 m/s

Explanation:

According to the equation of continuity discharge in the channel should remain same

Thus we have

$A_{1}V_{1}=A_{2}V_{2}$

For a rectangular channel we have $Area=Depth\times Width$

Applying values in the continuity equation and since the width of the channel remains constant 3.0 m we have

$3\times 1.8\times 1.2=3\times 3\times V_{2}\\\\\therefore V_{2}=\frac{6.48}{9}=0.72m/s$