有限振幅扰动下高超声速钝楔绕流感受性

为了研究自由流脉冲波作用下高超音速流动感受性特征，采用高阶有限差分方法模拟钝楔超高音速绕流中来流慢声脉冲波作用下的非定常流场，并应用傅里叶频谱分析了边界层扰动模态的演化.结果显示，自由流脉冲扰动下，边界层不同模态波沿流线呈现不同变化规律.球头区边界层感受到的主要是基频波，在球头向非球头区过渡段，主导模态迅速向高频迁移；在非球头区，主导模态频率缓慢向高频迁移.总的来说，沿流向总扰动模态中的低频模态成分变小，高频，特别是二阶谐频附近模态成分显著地增大.沿流线发展，边界层不同扰动模态之间存在伴随能量迁移的模态竞争物理现象，主导模态的发展对其他模态有很强的抑制作用.

Receptivity of hypersonic flow over blunt wedge under finite-amplitude disturbance wave

To investigate the receptivity characteristic of hypersonic flow under the action of free stream pulse wave, a high-order finite difference method was used to do numerical simulation of hypersonic unsteady flow over a blunt wedge with slow acoustic wave in free stream. The evolution of disturbance wave modes in boundary layer was analyzed by Fourier frequency spectral analysis. Results show that different frequency disturbance modes present different changes along streamline in boundary layer under freestream pulse disturbance. Disturbance waves in the boundary layer are mainly a fundamental mode. Ranging from the nose to the non-nose, the dominant mode shifts to high frequency rapidly; while in the region far from the nose, the shift to high frequency is very slow. In general, along the flow direction the low frequency component decreases quickly; the high frequency, especially the second harmonic mode component increases. Keen competition is accompanied by energy transformation exists among different modes in boundary layer. The dominant mode has an inhibitory action on the other modes.