Explain critical speed , White Water Rapids and turbulent flow .

Explanation

Critical speed : Steady flow is achieved at low flow speeds beyond a limiting value , called critical speed .
Turbulent flow : In a limiting value , called critical speed . "
Turbulent flow : In a fluid flow ,if the velocity of the fluid changes erratically from point to point as well as from time to time ,the flow is known as a turbulent flow.
If speed of fluid , becomes more to the critical speed ,this flow loses steadiness and becomes turbulent .
White water rapids : When a fast flowing stream encounters rocks , small foamy whirlpool like regions called white water rapids are formed

(a) Some streamlines for fluid flow.
A jet of air striking a flat plate placed perpendicular to it .This is an example of turbulent flow.