超音速自由せん断層の二次元組織構造モデル

抄録

The results of a numerical simulation provide theoretical insight into the large-scale eddy structure which is formed in a supersonic free shear layer. It is found that the experimentally measured asymmetry of convective Mach numbers of the two free streams is caused by an acoustic interaction of the disturbed shear layer with a remote flow channel wall. The resulting coherent vortical structure is analyzed to disclose that the straight undisturbed vortex sheet is deformed to a travelling wavy one, creating a train of twin disturbance vortices. Its phase speed deviates from the mean free-steam speed to a greater degree when the deformation of the vortex sheet and thereby the wave number are smaller. The vortices are elongated so as to avoid the formation of shock waves as the flow Mach number increases. The proposed physical model is also useful in investigating the mechanism of noises generated by supersonic jets.