What is the shear rate at the pipe wall, in case of laminar flow of Newtonian fluids in a pipe of diameter ‘D’ & length ‘L’ incurring a pressure drop ‘Δp’ with average velocity ‘Vavg’ ?
Correct answer: C
Explanation
For laminar flow in a pipe, the shear rate at the wall is given by $8V_{avg}/D$. This formula relates the average velocity to the wall shear stress.