Large-eddy simulation of reacting flows

A Large Eddy Simulation code is modified and adapted for multi-species and reacting flows. The code is designed to simulate compressible reacting turbulent flows and based on an explicit finite volume method. The numerical algorithm utilizes a Least Squares reconstruction of the flow variables on the cell faces. Inviscid fluxes are calculated by solving a Riemann problem for each face. The Roe split-difference approximate Riemann problem solver written for multispecies flows is used. Viscous fluxes are calculated by applying Gauss Theorem on each cell face. The MILES subgrid scale model is utilized for unresolved scales. Fast chemistry reaction model is utilized. Time integration is performed by the second order accurate Runge-Kutta scheme. The code is parallelized by domain decomposition and exchange of data between processors with the use of MPI software. The algorithm utilizes an unstructured grid composed of tetrahedra. The grid generation code was modified to include mesh discontinuity. The algorithm is validated by performing a series of test cases designed to validate different aspects of the physical problems. The problems include the Riemann shock tube problem to validate accuracy of compressible flow simulation, the decay of isotropic turbulence to validate proper modeling of turbulence properties and diffusion of species to validate the accuracy of the species diffusion mechanism. The calculation of the scramjet model test with the hydrogen jet exhausted from the base of the wedge in the coflowing air freestream was performed for reacting and non-reacting cases. The results were compared with Reynolds-Averaged Navier-Stokes code results and experimental data.