Numerical calculations of steady three-dimensional turbulent jets in cross flow

Abstract

This paper presents calculations of the steady flow of a row of turbulent jets issuing normally into a nearly uniform cross flow, using three-dimensional finite-difference numerical procedures. One procedure uses a quadratic upstream weighted (QUICK) difference scheme in representing the convection terms, while the other uses a hybrid central/upwind difference scheme. The calculations with the former are shown to be superior to those with the latter for all grid distributions. Fine grid calculations with the QUICK scheme are shown to agree fairly well with experimental measurements of total pressure distributions immediately downstream of the jet discharge. The agreement becomes worse further downstream, and it is shown that this may be due to the inablility of the k- ε turbulence model to correctly reflect the complex turbulent structure in the wake region. Estimates are provided of the relative magnitudes of the three-dimensional false or numerical diffusivities, resulting from the use of upwind differencing. The QUICK and hybrid schemes are shown to produce closer results when these false diffusivities are not much higher than the physical diffusivity.