Question

In both laminar and turbulent flow, is the pressure drop within a pipe with rough surface negligible or large?

Answer 1

*Friction loss is the major loss in flow through pipes is caused due to the viscosity of fluid against the wall of the pipe.

*In laminar flow, pressure loss or head loss are proportional to velocity of the liquid. So, it's considered negligible as pipe surface influences the liquid flow nor the loss due to friction.

*In turbulent flow, pressure loss or head loss are proportional to square of velocity of the liquid.

So, effect of pipe roughness has to be considered and pressure loss is large incase of turbulent flow.