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研究小攻角高超音速尖锥边界层的转捩预测问题.来流马赫数为6,锥的半锥角为5°,攻角为1°.采用传统的eN方法得到的转捩位置很不令人满意.原因在于,在传统的做法中,只考虑了增长中的扰动波,而事实上对于不同的子午面,扰动在开始增长前的衰减过程是各不相同的.根据我们以前的一些工作,对eN方法进行了新的诠释,并且提出实质上的改进.不仅考虑了扰动的增长过程还考虑了扰动的衰减过程.由线性理论计算得到的扰动从初始幅值增长到1%的位置被看作是转捩位置.这样得到的新的转捩预测结果相当令人满意.此外,对于基本流的计算,研究表明边界层方程可以用于小攻角的情况,其计算量远远小于直接数值模拟.
The hypothesis of hypersonic boundary layer transition at small angles of attack is studied.The Mach number of the incoming stream is 6, the half cone angle of the cone is 5 °, and the angle of attack is 1 ° The transfer position obtained by the traditional eN method is very weak The reason is that in the traditional approach, only the growing disturbance wave was considered, and in fact the disturbance process before it started to grow was different for different meridians. According to some of our earlier Work, a new interpretation of the eN method, and made substantial improvements not only consider the growth process of the disturbance but also consider the process of decay of the disturbance.The disturbance calculated by the linear theory increases from the initial amplitude to 1% Is considered to be a transitional position and the resulting new transition predictions are quite satisfactory.Furthermore, for the calculation of elementary flows, the study shows that the boundary layer equations can be used in small angles of attack, and the computational load is far less than Direct numerical simulation.