Numerical investigation of the high-speed conical flow past a sharp fin

Abstract

The supersonic flow past a fin mounted on a flat plate is simulated numerically by solving the Reynolds averaged Navier—Stokes equations. The results agree well with the experimental data. Post-processing of the numerical solution provides the missing flow-field evidence for confirming the currently accepted flow model, whose conception was based mainly on surface data. It is found that the flow is dominated by a large vortical structure, which lies on the plate and whose core has a remarkably conical shape with flattened elliptical cross-section. Along the fin and close to the corner, a slowly growing smaller vortex develops. On top of the conical vortex and along it a λ-shock is formed. Quantitative data are presented, which show that the flow is not actually purely conical but a small deviation exists, especially at the part between the separation shock and the plate. This deviation is detected when the stream wise extent of the flow is more than 20–30 initial boundary-layer thicknesses. Owing to the rather quasi-conical nature of the flow, the various flow variables do not remain constant along rays that start at the origin of the conical flow field, but they vary slowly. Data are presented which support the view that this deviation from conical behaviour is mainly due to the effect of the smaller rate of development of the boundary later of the plate, compared to the conical vortex.