湍流喷注噪声的压力关系

自五十年代以来,对亚声速及超声速喷注噪声有大量的研究工作,但对阻塞喷注的湍流噪声研究甚少。作者曾于文献[1]中提出阻塞喷注湍流噪声的压力关系。本文是以前工作的继续,作者发现只要将文献[1]中所提出的关系式略加修改,适用范围便可以延至亚声速喷注。并得到湍流喷注噪声的发生机理。根据这个关系,可以推论喷注中的湍流噪声,无论是阻塞或非阻塞,来源都是湍流脉动的四极子源,只是在阻塞喷注中湍流速度继续随驻点压力增加,虽然气流的平均速度不再改变。作者还提出了湍流速度变化的规律,它的合理性及导出的噪声公式为实验结果所证明。

PRESSURE DEPENDENCE OF TURBULENT JET NOISE

Ever since the fifties, profound theoretical and experimental investigations were spent on the noise production of subsonic and supersonic jets, but little has been done on the turbulent noise of a choked jet. In a previous paper the authors derived the pressure dependence of the latter. In this paper it is shown that a slight modifica-tion of the formula in the above-mentioned paper will make it applicable to subsonic jets too, and an interpretation is obtained for turbulent jet noise in general. From this it is inferred that turbulent jet noise has its origin in the quadrapole radiation of turbulent eddies, the only difference in that, for a choked jet, the turbulence velocity further increases with the stagnation pressure, although the mean jet velocity does not. From this point of view, the rule of increase of the turbulent velocity with increasing stagnation pressure is predicted. This interpretation seems plausible and the noise relations thus derived agree with experiment.