Computation of the Viscous Supersonic Flow over External Axial Corners

Abstract

The viscous supersonic flowfield surrounding symmetric and asymmetric swept external axial corners is computed using existing second-order, implict and explicit finite-difference computer codes. The governing partial differential equations in conservation-law form are hyperbolic with respect to time and are assumed to be conical; that is, any variation of the radial convective or diffusive terms is assumed to be negligible. An inviscid numerical study for symmetric 90 deg dihedral rounded corners reveals both single and triple crossflow stagnation point flows, depending on the corner radius of curvature. For asymmetrical 90 deg dihedral configurations (i.e., those obtained by varying one of the wedge angles), both single and triple stagnation point flows are also observed. For certain highly asymmetrical configurations, the inviscid flow spills over the corner and in so doing generates a local embedded supersonic bubble. Viscous numerical solutions are obtained for both symmetric and highly asymmetric axial corners for which experimental surface oil flow and vapor screen data are available. For the symmetric configuration, both the laminar and turbulent numerical solutions result in flow away from the corner, which agrees with the experimental data. For the highly asymmetrical configuration, the viscous numerical solution and the experimental data result in flow around the corner. The computed shock locations for both configurations agree fairly well with the experimental vapor screen results.