尾迹流中大尺度涡的三维理论模型

A 3-D THEORETICAL MODEL FOR THE STRUCTURES OF LARGE-SCALE VORTICES IN THE WAKE

根据流动稳定性理论,在边界层外区大尺度涡理论模型的基础上提出了一种解释尾迹流中大尺度涡产生机理的三维理论模型。采用该模型对NACA0012翼型尾缘后0．1到0．3倍弦长区域的流动进行计算,得出的流场结构及大尺度量的等值线等与实验符合一致,说明该理论模型能够很好地捕捉到尾迹流中大尺度结构的主要特征。该模型的提出为开展尾迹型流动的实验和数值模拟研究提供理论支持,同时为研究尾迹对流动的影响,特别是叶轮机内部的流动前一级叶栅尾迹对下一级叶片边界层的干扰提供了很大的简化。

Based on the theory of flow instability and theoretical model of boundary layer, a new theoretical model of 3-D wave model for the large-scale vortices structures in the wake region was proposed to interpret the mechanics of large-scale vortices occurrence. The, flow field behind an airfoil from 0.1 L to 0.3 L was calculated. As a result, the streamlines and the contours of large-scale variables were obtained, and they were in good agreement with those of experimental observations. It can be concluded that this model can describe the physical mechanism of the large-scale vortices in the wake region. The model enriched wake flow theory, so it is more convenient to undertake the experiment and numerical simulation of wake-type flow. It is a good model to simplify the problem when researches on the effect of wake on flow field, especially the effect of wake from the last cascade on the next cascade are needed.