Shear rate at the inner wall of a Newtonian fluid (flowing within a pipe)


A Newtonian fluid is a fluid in which the viscous stresses arising from its flow, at every point, are proportional to the local strain rate — the rate of change of its deformation over time. That is equivalent to saying that those forces are proportional to the rates of change of the fluid’s velocity vector as one moves away from the point in question in various directions. The shear rate for a fluid flowing within a pipe is related to the fluid velocity and the inside diameter of the pipe.

Related formulas


γShear rate (1/s)
vVelocity of the fluid (m/s)
dInside diameter of the pipe (m)