基于KL分解的翼型尾流场湍流相位特征PIV试验研究

Experimental investigation of airfoil wake phase-averaged turbulence characiteristics based on KL decomposition by PIV

翼型尾流场是一个典型的湍流场,通过对其进行PIV测试研究,有望对翼型尾流的湍流发生机理有一个更深入的理解,并且为湍流诱导流噪声的研究提供重要的参量,具有重要的意义。通过对PIV数据进行雷诺平均分析,可以得出时间平均意义下的大尺度涡结构的平均运动规律,但无法得到小尺度湍流结构的周期性演化规律,而对于充分发展的平稳湍流场来说涡的发放通常是具有周期性的。基于KL分解的湍流相位特征分析方法能够提取小尺度湍流运动并揭示其演化的周期性规律。缘于此,此文在CSSRC空泡水筒中开展了翼型尾流场PIV测量试验,基于KL分解原理对翼型尾流场进行相位分解并进行了各相位湍流流动特征分析,探索湍流结构的周期性演化规律。

The wake behind an airfoil is a typical turbulent flow.Through experimental investigation by PIV,we can get some important insight in the turbulence inception,and it may play a significant role in providing important parameters for the experimental investigation of turbulence-induced flow noise.The time-averaged large scale vortex structure and its evolution can be obtained through Reynolds decomposition,but it is still very hard to get the periodical evolvement rule of small scale turbulent motions,which is an important characteristic in fully developed turbulence.Fortunately,KL Decomposition provides the feasibility of exploring that very important rule.Based on it,an experimental investigation of an airfoil wake by PIV is carried out in CSSRC Cavitation Tunnel and the phase-averaged turbulence characteristics and the periodical evolution rule is analyzed in this paper.