Investigation of an asymmetrical shock-wave boundary-layer interaction in a supersonic planar nozzle

When thrust nozzles are designed for high-altitude flight regimes, the propulsive jet is no longer adapted for operation at ground level and at low altitude. Thus, the nozzle operates in over-expanded regime. Unsteadiness due to the boundary layer/shock interactions in the divergent part of the nozzle can produce non-symmetric side loads that can damage the structure. The need for a complete understanding of this phenomenon and the validation of numerical methods and turbulence models able to predict this phenomenon has motivated a basic experiment aimed at producing an exhaustive set of experimental data. The test configuration made up of a rectangular nozzle and set up in a supersonic wind tunnel has allowed us to obtain a non-symmetric interaction whose unsteady aspects have been analyzed. This program was completed by numerical simulations of the flow in its mid-longitudinal symmetry plane. The goal was to test the capabilities of RANS (Reynolds Average Navier-Stokes) calculations in predicting the mean interacting flow through the use of three two-equation turbulence models. Two models, recently tested in the case of transonic and supersonic separations, compared with the Jones-Launder model, have given close results. Experimental and theoretical data have constituted the matter for a general discussion of the validation of turbulence models in channel flows where acoustic disturbances appear. © 2005 CASI.