SUPPRESSION OF EMBEDDED SHOCKS IN SUPERSONIC FREE-SHEAR-LAYER STRUCTURES

Although the suppressed instability of supersonic free shear layer flo w has been documented by many investigators, the underlying physics ar e still ambiguous. In the present study, numerical simulations were pe rformed to cast physical insight into the two-dimensional large-scale structure which is organized in a supersonic free shear layer. It is f ound that an acoustic interaction of the disturbed shear layer with a flow channel wall or another shear layer is indispensable to generate the organized structure. The undisturbed vorticity layer is deformed i nto a traveling wavy one. As the flow Mach number increases, its degre e of deformation decreases so that the formation of shock waves embedd ed in the structure is avoided.