噪声对边界层转捩的影响

风洞流场的噪声和湍流度是影响层流边界层转捩实验结果的两个重要因素。本文通过实验初步研究了噪声对转捩的影响，实验包括：输入声影响和风洞流场的噪声。结果表明：声频和声压在数值上都存在敏感区，风洞噪声是宽带噪声，以低频为主（至少低速风洞是如此），这对层流边界层转捩有重要作用；风洞噪声会随风速加大而增高；在稳定段用栅格改变湍流度时，实验流场的噪声会随湍流度升高而增加。

EFFECT OF THE NOISE ON BOUNDARY LAYAR TRANSITION

in test section of wind tunnel, the stream turbulence and the stream noise are two important factors effecting on experimental results of laminar boundary layer transition. In this paper, an experimental study on effect of stream noise on boundary layer transition has leen conducted, that consists of two parts, (1) effect of input sound on boundary layer transition,(2) measure of stream noise in test section.Results of this paper show that: there are sensitive region of frequency and pressure of sound effecting on boundary layer transition, frequency band of stream noise in test section is wide, and the low frequency is dominant and important to effect on boundary layer transition, stream noise increases while wind velocity increases or turbulence raises with adding grid in settling chamber.