The Numerical Study Of Evolution Of Perturbations In The Supersonic Blunted Cone Boundary Layer Flow

As the aero technology developing, the problem of stability and transition in compressible supersonic boundary layer has attracted more and more attention. In practical, supersonic cone shape boundary layer is a model being widely used, and due to the fact that there is no purely sharp cone in engineering. In this paper, the evolution of disturbances in the hypersonic blunt cone boundary layer has been studied numerically.In this paper, the special evolution of disturbances in hypersonic blunt cone boundary layer with the oncoming flow of Mach 6 and semi-angle of 5 degree was investigated by direct numerical simulation (DNS). A small region close to the wall was chosen, and the simulation with high accuracy compact scheme in body-fitted coordination system was executed. And then, T-S waves were introduced at the entrance of the computational domain to study the special evolution, and whether the secondary instability mechanism exists in the supersonic blunted cone boundary layer was examined, too.The conclusions was as follows: when the amplitude of disturbance was small, the amplitude and phase of disturbance wave during the evolution would agree well with the results obtained by the linear stability theory with the hypothesize of parallel flow; which meant the non-parallel effect may be ignored in blunt cone boundary layer, too; when the value of the disturbance amplitude enlarged to some finite value, the harmonic waves occurred with the effect of nonlinear, the mean flow profile was modified, the amplified rate of the disturbance was far less than the LST's ,and the profile of the disturbances was different from the small one.