The mean flowfield structure in the wake region of a circular cylinder at 10° angle of attack in Mach 2.5 flow is described. Results from the full three-dimensional Reynolds averaged Navier-Stokes equations, supplemented with a compressibility-corrected two-equation turbulence model, are compared with extensive available experimental data. The main elements of the shock pattern, surface oil flow on the afterbody and the base surfaces, velocity vector plots in the symmetry and lateral planes and end-view flow images are reproduced to good accuracy. Based on this success, the computed solution is employed to generate a model for the mean flow. The main feature is a pair of longitudinal vortices, separated by high-speed fluid entrained primarily from the leeward and lateral afterbody boundary layers, and bounded from below by the windward afterbody boundary layer. The three-dimensional wave structure is elucidated and correlated with the streamline structure. Vorticity distribution analysis indicates that in the mean flow description, the vortex cores are two legs of a horseshoe-like structure. The predictive capability of the present RANS approach is baselined for future detached eddy simulations by comparing mesh resolved surface pressures on the afterbody and the base region: these are found to differ by between 10% to 15%.
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