As can often be seen in a kitchen sink when the faucet is running, a high-speed channel flow (V1, h1) may jump to a low-speed,

As can often be seen in a kitchen sink when the faucet is running, a high-speed channel flow (V1, h1) may €œjump€ to a low-speed, low-energy condition (V2, h2) as in Fig. P3.102
The pressure at sections 1 and 2 is approximately hydrostatic, and wall friction is negligible. Use the continuity and momentum relations to find h2 and V2 in terms of (h1, V1).

Hydrauic jump