A person standing on the bank of a canal drops a stone on the water surface. He notices that the disturbances on the water surface is not travelling upstream. This is because the flow in the canal is-

Correct option is B

1. Sub-critical Flow
→ The flow is dominated by gravitational forces.
→ Disturbances can travel both upstream and downstream.
2. Critical Flow
→ The flow velocity equals the wave propagation speed.
3. Super-critical Flow
→ The flow is dominated by inertial forces.
→ Disturbances cannot travel upstream as the flow velocity is greater than the wave propagation speed.