Investigation of transonic bi-convex corner flows

Experiments were performed to investigate a transonic, turbulent boundary layer over a bi-convex corner. The total turning angle η ranged from 10 deg to 17 deg. In subsonic expansion flows, the presence of a bi-convex corner results in a decrease in local peak Mach number M peak and the amplitude of peak surface pressure fluctuations ( σ p / p w ) max . There is a delay in transition from subsonic to transonic expansion flows. A dual expansion is observed in transonic expansion flows. Shock structure, boundary-layer separation and ( σ p / p w ) max were dependent on freestream Mach number M, first turning angle η 1 and η. The length of the first corner L 1 also plays an important role. An increase in L 1 results in less flow expansion, while a decrease in the amplitude of ( σ p / p w ) max is associated with a shorter L 1 .