In the region just downstream of a sluice gate, the water may develop a reverse flow reg...

In the region just downstream of a sluice gate, the water may develop a reverse flow region as indicated in Fig. P4.34 and Video V10.11. The velocity profile is assumed to consist of two uniform regions, one with velocity V_a=10 fps and the other with V_b=3 fps. Determine the net flowrate of water across the portion of the control surface at section (2) if the channel is 20 ft wide.