Numerical vs experimental pressure drops for Boger fluids in sharp-corner contraction flow

Abstract

This paper addresses the problem of matching experimental findings with numerical prediction for the extreme experimental levels of pressure-drops observed in the 4:1 sharp-corner contraction flows, as reported by Nigen and Walters [“Viscoelastic contraction flows: Comparison of axisymmetric and planar configurations,” J. Non- Newtonian Fluid Mech. 102, 343–359 (2002)]. In this connection, we report on significant success in achieving quantitative agreement between predictions and experiments. This has been made possible by using a new swanINNFM model, employing an additional dissipative function. Notably, one can observe that extremely large pressure-drops may be attained with a suitable selection of the extensional viscous time scale. In addition, and on vortex structure, the early and immediate vortex enhancement for Boger fluids in axisymmetric contractions has also been reproduced, which is shown to be absent in planar counterparts.