Question

Two point method is used for measurement of velocity in a triangular channel having top width equal to 5 m and depth equal to 2 m. The measured velocities along the center line at 0.4 m, 1.5 m and 1.6 m below the surface are 0.8 m/s, 0.5 m/s and 0.4 m/s respectively. The discharge through the stream is

• A. 6
• B. 9
• C. 10
• D. 3

Answer 1

The correct option is D 3

Using two point method
$V=\frac{V_{0.2}+V_{0.8}}{2}=\frac{0.8+0.4}{2}=0.6m/s$
$\therefore \text{Discharge,}Q=A\times V$
$=\frac{1}{2}\times 5\times 2\times 0.6=3m^3/s$