中文摘要：

利用粒子示踪图像流动显示技术和粒子图像测速技术（PIV技术）研究了对流马赫数Mc=0．38时可压缩混合层发展早期出现的大尺度结构的形状和特性，并将这些混合现象与湍流脉动场结合起来研究了这些大尺度结构对流动混合效率的作用。将粒子示踪图像和湍流脉动强度场对比以后发现：混合层流动中早期出现的大尺度结构沿着顺时针方向旋转着向前移动；该结构上的流体微元具有高涡量。由于该结构旋转和高涡量产生了较大的诱导速度，加上该结构的非定常性导致在这些大尺度结构频繁出现的区域具有很高的脉动强度，从而可能带来较高的混合效率。

英文摘要：

Using seeded particle image and particle image velocimetry（PIV） technique, the shape and characteristic of large-scale structure displayed in early mixing process at（convective Mach number） Mc= 0.38 has been studied. Compared visualization images obtained from particle trace technique with the distribution of turbulent intensity, it is observed that the large-scale structure presented in compressible mixing layer moves forward with clockwise rotation and a flow particle on this structure has a high vorticity. The high induced velocity produced by this structure and its unsteadiness results in higher turbulent fluctuation velocity and then brings into possibly higher mixing efficiency.