Question

Explain how you may determine if flow in a pipe is laminar or turbulent? Why is the distinction between laminar and turbulent important in fluid mechanics?

Answer 1

In laminar flow ,one layer of the liquid slides parallel to other layer and there would be no momentum transfer between different layer however if water goes from one layer to other layer ie the various layer slides over each other then this type of flow is known as turbulent flow .In turbulent flow the transfer of momentum also takes place.

We can differentiate between laminar and turbulent flow on the basis of Reynolds number(Re),for circular pipe Re is given as

Re < 500 then flow is laminar and if

Re>200 the flow is turbulent

Between 500 and 2000 the flow is in transient state