ABSTRACT

We present a systematic approach to extract the characteristic vortex region that contains the essential features of a complex flow field. The process involves the analysis of the complex eigenvalues of the velocity gradient tensor. In particular, we propose the analysis using the joint and marginal probability distributions of the complex eigenvalues of the velocity gradient tensor that preserves the sufficient swirling strength and the required orbital compactness of the swirling orbits defining the vortex region. We consider three complex flow scenarios for the application and the assessment of the proposed approach: (i) rotating Rayleigh–Benard convection, (ii) turbulent channel flow, (iii) turbulent flow field in a cylindrical cyclonic separator. While problem (i) is considered for the extraction of subsumed cyclonic structure, problems (ii) and (iii) are reminiscent of wall-bounded turbulent flows, relevant for different industrial applications.

摘要

我们提出了一种系统方法来提取包含复杂流场基本特征的特征涡流区域。该过程涉及对速度梯度张量的复特征值的分析。特别是，我们建议使用速度梯度张量的复特征值的联合和边缘概率分布进行分析，该分布保持足够的旋流强度和定义涡流区域的旋流轨道所需的轨道紧凑性。我们考虑了三种复杂的流动场景，并评估了所提出的方法：（i）旋转瑞利-贝纳德对流，（ii）湍流通道流，（iii）圆柱形旋风分离器中的湍流流场。虽然问题 (i) 被考虑用于提取包含的气旋结构，