稳定分层湍流的PIV实验研究

在自行建立分层湍流实验装置的基础上,进行了一系列分层湍流的实验研究,运用激光诱导荧光(LIF)流动显示技术和PIV流场测量技术,定性研究了剪切和分层对湍流混合和湍流结构的影响.实验结果发现:剪切促进湍流混合,稳定分层抑制湍流混合,而且分层使得混合层内的湍流结构变得扁平和细长,同时还发现了混合层内涡旋的拉伸、合并、扭曲和变形等复杂的流动现象,特别是发现了其中的旋转涡对和反旋转涡对以及对湍流输运起重要作用的手指状结构.

Experimental study of stratified turbulence using PIV system

In this paper,the system of experimental facilities on turbulent stratified flow were constructed in our laboratory,and a set of experiments were conducted in two kinds of water flows,neutral and stratified flow,using laser induced fluorescence(LIF) and particle image velocimetry(PIV).The effects of the mean shear and stratification were investigated qualitatively.It shows that,turbulent mixing is improved by mean shear but impressed by stratification;the large scale structures are restricted within the mixing layer,particularly in stratified case.The structures in the mixing layer become more compressed and threadlike with the effects of stable stratification.In addition,very complicated phenomena of stretching,uniting and distorting between vortexes are found in the mixing layer and nearby the interface,remarkably the revolving and antirevolving vortex pairs and the finger-like structure are discovered in the flow visualization.