PREDICTIONS OF AXISYMMETRICAL AND 2-DIMENSIONAL IMPINGING TURBULENT JETS

The k-epsilon turbulence model and a version of a second-moment closur e, modified to include the effect of pressure reflections from a solid surface, have been used as the basis of predictions of the flow that results from the orthogonal impingement of circular and two-dimensiona l (2-D) jets on a flat surface. Comparison of model predictions has be en made with velocity measurements obtained in the stagnation and wall jet regions of the impinging flows, Results, in general, confirm the superiority of the Reynolds stress transport equation model for predic ting mean and fluctuating velocities within the latter regions of such flows. In particular, modifications to the second-moment closure to a ccount for the influence of the surface in distorting the fluctuating pressure field away from the wail successfully predict the damping of normal-to-wall velocity fluctuations throughout the impinging flaws. I n contrast, results derived from the eddy-viscosity-based approach do not, in general, accurately reproduce experimental observations. (C) 1 996 by Elsevier Science Inc.