6. An increase in roughness of a pipe with laminar flow would increase the pressure drop...

6. An increase in roughness of a pipe with laminar flow would increase the pressure drop of the pipe. Assume the velocity is the same for the smooth pipe and the rough pipe.

a. True

b. False

Solutions

Expert Solution

b. False

For a pipe with laminar flow, the pressure drop is independent of the roughness of the pipe unlike the pipes with turbulent flow.

In case of laminar flow through a pipe, the pressure drop per length is characterized by the Hagen-Poiseuille equation, which is given by:

where ?P is the pressure drop

is the kinemat viscosity

V is the velocity

D is the diameter of the pipe

Here, the pressure drop is directly proportional to the velocity and it is independent of the friction factors (ie, roughness). But here it is given that the velocity is same for both pipes. Hence there will not be any change in pressure drop.

samet mamat answered 1 year ago

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