The inviscid impingement of a jet with arbitrary velocity profile

Abstract

Accurate determination of wall shear stress and heat and mass transfer rates under an impinging jet requires careful analysis of the boundary layer at the impingement surface due to the large pressure gradients near the stagnation point. Modeling the inviscid flow just outside the boundary layer provides the boundary conditions necessary for such an analysis. Previous inviscid models have considered only a small subset of possible jet velocity profiles and with limited spatial resolution. In the present work, analytical solutions to the stream-vorticity equation for two-dimensional and axisymmetric impingement flow with arbitrary velocity profile are found in terms of a surface integral involving the vorticity function, allowing an iterative determination of the stream function throughout the impingement region. Surface pressure distributions and streamline plots are calculated for various impinging jet configurations, including plane, round, and annular jet nozzles. The calculations show excellent agreement with previous experimental and numerical results, while requiring relatively short computation times. Flow predictions are also made for impinging jet configurations for which no previous data or calculations exist. (C) 2000 American Institute of Physics.