Large-Eddy Simulation in the Near-Field of a Transient Multi-Component Gas Jet with Density Gradients

Large-eddy simulation (LES) is a research tool that is increasingly being used to study practical engineering flows because of continuous improvements in computational power. This paper outlines an LES model developed for the study of multi-component transient gas jets with density gradients. The compressible LES formulation together with the numerical model, boundary conditions, perturbation, and parallelization are discussed. A non-dissipative sixth-order finite difference scheme is used to discretize the governing equations, and a low-pass sixth-order spatial filtering scheme is employed to avoid the growth of high-frequency modes. The conditions at the boundaries are implemented using Navier–Stokes characteristic boundary conditions. In addition to code performance, results are presented from a study of an impulsively started jet at high pressure and temperature with an injected to ambient gas density ratio of approximately 3.5.