Numerical aspects for physically accurate Direct Numerical Simulations of turbulent jets

Abstract

Numerical simulations of turbulent isothermal round jets are performed at Reynolds number (based on jet diameter and jet orifice velocity) of 5000 and Mach number of 0.6 to assess influences of initial perturbation, numerical characterization, and boundary treatments on turbulence statistics. The aper documents preliminary results from an investigation eventually aimed at examining multicomponent species injection and mixing at high-pressure conditions relevant to combustion in diesel, gas-turbine and liquid-rocket engines. Lack of reliable experimental or computational results at high pressures of interest make code validation at those conditions infeasible. Therefore, single-species simulations at perfect-gas conditions are first performed to assess turbulence statistics sensitivity to numerical setup. Two cases with different inflow velocity perturbation amplitude are considered to examine influences on jet flow transition and self-similarity.