摘要
采用高阶精度的有限差分方法直接数值模拟了钝楔高超声速绕流自由来流慢声波扰动非定常流场,比较了来流脉冲波与连续波作用下高超声速边界层扰动模态的演化,并着重讨论了壁温对边界层扰动模态演化的影响。结果显示,无论脉冲波还是连续波,钝楔边界层球头区感受到的都主要是基频波,无论基频还是谐频,脉冲波作用下的边界层不稳定扰动模态的增长远小于连续波情形。对于脉冲波,在球头区,所有模态迅速衰减,在非球头区,主导模态迅速由低频向高频迁移,不同频率模态有不同的变化趋势,总的来说,沿流向总扰动模态中的低频模态成份减少,高频模态成分增大。壁温条件对基频扰动模态影响相对较小,而对高频扰动模态的演化有显著影响,冷壁总体上加速了边界层高频不稳定扰动模态的发展,抑制了低频模态沿流线的衰减。
A high-order accurate finite difference method is employed for direct numerical simulation of hypersonic unsteady flow over a blunt wedge with slow acoustic wave disturbance in incoming stream. The differences of disturbance modal development in boundary layer between pulse wave and continuous wave are compared, and the effects of wall temperature on the development of disturbance mode in hypersonic boundary layer are mainly discussed. The results show that fundamental frequency mode is the strongest disturbance in the nose tip hypersonic boundary layer for both pulse wave and continuous wave. The growth of unstable mode in boundary layer under the action of pulse wave is much smaller than that under the action of continuous wave for both fundamental frequency and harmonic frequency. For pulse wave, all disturbance mode degenerates along the flow direction within a nose radius; while in the region far from the nose the dominant mode shifts to high frequency. The development of different mode varies each other. In general terms, from upstream to downstream, the high frequency components increase quickly and low frequency components almost are restrained to grow. The results also show that wall temperature has less influence on fundamental frequency, while the development of high frequency mode is affected significantly. Cooling the wall accelerates the development of high frequency, and inhibits the degeneration of low frequency mode along the streamwise.
出处
《宇航学报》
EI
CAS
CSCD
北大核心
2014年第4期481-490,共10页
Journal of Astronautics
基金
国家自然科学基金(11272096)
高等学校博士学科点专项科研基金(20112304110015)
中央高校基本科研业务费资助(HEUCF130216)
