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在美国阿诺德工程发展中心冯·卡门设备上,利用激光干涉仪技术来确定超音速和高超音速风洞中试验模型上的边界层状态特征。边界层转捩探测器是根据激光横向干涉原理制成的,可用来测定可压缩流动内边界层的湍流频谱。使一束激光通过边界层,另一束参考激光在边界层之外,监测由这两束激光形成的干涉条纹的相移,即可实时探测由空气密度的起伏所表示出的湍流度。本方法对流场不产生扰动,而其它一些常用的方法(如比托管探针和热线风速仪)则对流场有扰动。文中给出了表明边界层从层流转捩成湍流的数据,把该探测器的测量结果与别的测量方法作了比较。
At the Arnold Engineering Development Center von Karman facility, the laser interferometer technique was used to determine the boundary layer state characteristics of the experimental model in supersonic and hypersonic wind tunnels. The boundary layer transition detector is based on the laser transverse interference principle and can be used to determine the turbulence spectrum of the compressible flow inner boundary layer. A laser beam is passed through the boundary layer and the other reference laser is outside the boundary layer. The phase shift of the interference fringes formed by the two laser beams is monitored to detect in real time the turbulence indicated by the air density fluctuations. This method does not perturb the flow field, while other commonly used methods (such as the Managed Probe and Hot Wire Anemometer) perturb the flow field. The data given in this paper show that the boundary layer turns from laminar to turbulent, and the measurement results of the detector are compared with other measurement methods.