The effect of mesh refinement on the computation of entrance effects for shear‐thinning fluids

The effect of mesh refinement on the finite element computation of velocity and pressure is assessed for the creeping flow of a power law fluid and a Carreau fluid through an axisymmetric sudden contraction. The emphasis is placed on the determination of the entrance pressure correction n ent . The augmented Lagrangian formalism is used and the discretization of the variational problem is based on the Crouzeix‐Raviart triangular element. For power‐law fluids, it is found that fine meshes yield values of n ent which are significantly lower than those obtained in previous numerical studies, especially for high shear‐thinning fluids. A similar trend is observed in the Carreau model.