Large-Eddy/Reynolds-Averaged Navier-Stokes Simulation of Shock-Train Development in a Coil-Laser Diffuser
Final rept. 1 January 2013-6 September 2014
NORTH CAROLINA STATE UNIV AT RALEIGH
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This report describes the application of a hybrid large-eddy simulation Reynolds-averaged Navier-Stokes method to predict shock train formation and reactant mixing in a model Chemical Oxygen Iodine Laser COIL unit. The configuration consists of a converging-diverging nozzle, a lasing cavity, and a diffuser. Results have been obtained for several grids and for several back pressures, the variation of which fixes the average shock-train position within the nozzle. Predictions of wall pressure are in reasonable accord with experimental observations for both LESRANS and RANS model but tend to under-predict the initial rate of pressure increase as the flow encounters the leading edge of the shock train. Though the shock train induces a transition to turbulence as well as local flow separation, the effects of resolved turbulence and unsteady separation do not appear to influence the mixing process in the lasing cavity significantly.
- Lasers and Masers