Reynolds Number Dependence of Higher Order Statistics for Round Turbulent Jets Using Large Eddy Simulations

Despite the large repository of experimental and computational studies on the topic of turbulent jets, inconclusive and conflicting estimates prevail in regard to certain terms in the turbulence energy budget and the dependence (or lack of dependence) of these and other flow physics on the jet Reynolds number. No comprehensive study exists which adequately addresses these inconsistencies. The purpose of this study is to resolve these contradictions and ascertain the true dependence of the flow statistics on the jet Reynolds number. This is accomplished through high fidelity Large Eddy Simulations (LES), which are performed for a single isothermal round jet at three different Reynolds numbers, encompassing nearly two orders of magnitude. In each case, results are compared to well-accepted experimental and computational studies, and excellent agreement is found with experimental quantities either directly acquired or computed directly from raw data. A separate discrete eddy simulation of the flow in the nozzle upstream of the jet inlet is performed and is found to be crucial in quantifying the flow physics in the near field (e.g., virtual origin). Results show a definite Reynolds number dependence for nearly all third order terms and this is non-negligible especially for the mean convection and production terms in the turbulent kinetic energy budget.