The Rabinowitsch (or Weissenberg-Rabinowitsch) correction is applied to get more accurate shear rate values from Non-NewtonianA non-Newtonian fluid is one that exhibits a viscosity that varies as a function of the applied shear rate or shear stress.non-Newtonian materials measured using a capillary flow technique.
The basic shear rate equation for capillary flow is based on Newtonian fluids, where the velocity profile from pressure-driven flow in a capillary is shown to be homogenous (parabolic); however, for Non-NewtonianA non-Newtonian fluid is one that exhibits a viscosity that varies as a function of the applied shear rate or shear stress.non-Newtonian fluids such as the Shear ThinningThe most common type of non-Newtonian behavior is shear thinning or pseudoplastic flow, where the fluid viscosity decreases with increasing shear.shear thinning behavior of polymer melts, the inhomogeneous flow contributes to what can sometimes be significantly higher shear rates at the boundary wall.
The correction takes into account the non-parabolic velocity flow where the shear rate at the wall is usually higher.
For fluids obeying the Power Law, the correction is simply, the
where γa is the apparent shear rate at the wall and n is the Power Law index.