iv$.$ The boundary

v$/$ The boundary layer thickness decreases as the

How does the surface roughness of a pipe affect the type of flow and the critical

Reynolds number for the transition from laminar to turbulent flow?

i$.$ Increased roughness has no effect on the critical Reynolds number or flow type.

ii$.$ Increased roughness reduces the critical Reynolds number, making the transitio

turbulent flow more likely at lower velocities.

iii. Increased roughness increases the critical Reynolds number, delaying the transi

turbulent flow.

iv Surface roughness only affects the flow if the flow is already turbulent.

v$.$ None of the above statements correctly explain the effect of surface roughness

flow transition.