超音速尖锥边界层中扰动演化特征的数值研究

Numerical Investigation of the Evolution of Disturbances in Supersonic Sharp Cone Boundary Layers

采用高精度紧致格式,对超音速尖锥边界层中二维扰动的空间演化,进行了直接数值模拟.结果表明,虽然尖锥边界层流动存在一定的锥面法向速度,但小扰动的幅值及相位的演化都与由平行流假设得到的线性理论结果吻合.还研究了有限幅值扰动的演化,给出了其演化规律.并在扰动幅值增长到一定值时,发现了小激波.

The spatial evolution of 2-D disturbances in supersonic sharp cone boundary layers was investigated by direct numerical simulation （DNS） in high order compact difference scheme. The results obtained suggested that although the normal velodty in the sharp cone boundary layer is not small, the evolution of amplitude and phase for small amplitude disturbances would be well in accord with the results obtained by the linear stability theory （LST） which supposes the flow is parallel. The evolution of some finite amplitude disturbances was also investigated, and the characteristic of the evolution was shown. And shocklets were also found when the amplitude of the disturbances over some value.