Remarks on numerical prediction of wall shear stress in entry flow problems

Today, commercial CFD codes are widely used to simulate many different entry flow problems. The flow in the developing zone undergoes a transition from a specified velocity profile at the inlet section to a fully developed profile in the region far from the inlet. Previous investigations have shown that the hydrodynamic variables, such as velocity and pressure magnitudes, along the centreline converge to a mesh independent solution even when coarse grid distributions are utilised. However, the present work shows that the local velocity profile is highly dependent on grid resolution in the vicinity of solid boundaries. It is shown that failure to account for the grid resolution can result in significant errors in the predicted solid-fluid interaction, e.g. wall shear stress calculation. A remedy to overcome this problem is subsequently given. Copyright (C) 2004 John Wiley Sons, Ltd.