Large-Eddy Simulation of Jet Mixing in Supersonic Crossflows

摘要

Large-eddy simulation of an underexpanded sonic jet injection into supersonic crossflows is performed to obtainninsights into key physics of the jet mixing. A high-order compact differencing scheme with a recently developednlocalized artificial diffusivity scheme for discontinuity-capturing is used. Progressive mesh refinement study isnconducted to quantify the broadband range of scales of turbulence that are resolved in the simulations. Thensimulations aimto reproduce the flowconditions reported in the experiments of Santiago andDutton [Santiago, J.G.,nand Dutton, J. C., “VelocityMeasurements of a Jet Injected into a Supersonic Crossflow,” Journal of Propulsion andnPower,Vol. 132, 1997,pp. 264–273] andelucidate thephysics of the jetmixing.Adetailedcomparisonwiththesedataisnshown. Statistics obtained by the large-eddy simulation with turbulent crossflow show good agreement with thenexperiment, and a series of mesh refinement studies shows reasonable grid convergence in the predicted mean andnturbulent flow quantities. The present large-eddy simulation reproduces the large-scale dynamics of the flow and jetnfluid entrainment into the boundary-layer separation regions upstreamand downstreamof the jet injection reportednin previous experiments, but the richness of data provided by the large-eddy simulation allows a much deepernexploration of the flowphysics.Key physics of the jetmixing in supersonic crossflows are highlighted by exploring thenunderlying unsteady phenomena. The effect of the approaching turbulent boundary layer on the jet mixing isninvestigatedbycomparing the resultsof jet injectioninto supersonic crossflowswithturbulent andlaminar crossflows.