Articles techniques et présentations

This study investigates the shock boundary layer interaction occurring at the base of a double sharp fin. The base geometry is of particular interest, with comparisons made between flat and semi-cylindrical bases. The flow field is characterized via numerical simulations and identifications of vortices in the flow field are made. There have been many studies on the shock boundary layer interaction generated by fins located on flat surfaces, but relatively few on fins located on semi-cylindrical surfaces. It is observed in supersonic flow past a fin that the fluid in the contact region between the fin’s root and the semi-cylinder exhibits turbulent phenomena, and the angle between the shock wave and the fin will decrease continuously as the Mach number increases. The separation shock will continuously move towards the fin root, and the vortex generated by the fin will reduce the speed of the fluid passing over the surface of the fin. After comparing separation vortices generated by plate-based fins and semi-cylinder fins, vortices generated by both the downwind fin and upwind fin rotate in the same direction in the semi-cylinder fin model, but separation vortices will change direction in downwind plate-based fin model. For the downwind plate-based fin, separation vortices will rise near the fin and descend far from the fin. Further examination of the relationship between the Strouhal number and the Reynolds number will assist designers in predicting the behavior of aircraft under different speed conditions.