A Simple Vortex Structure Identification for Unsteady Flow Field Analysis

Abstract

A simple method for identifying vortex structures is proposed for the analysis of unsteady flow fields. The proposed method is applied to the flow field around NACA0015 airfoil to extract and visualize vortex structures. As the result of applying to the flow field, it is shown that the results are comparable to the isosurfaces of the second invariant of the velocity gradient tensor. In addition, by visualizing multiple time series data at once using only those with dominant spanwise vorticity components, it is shown that the advection and location of vortex breakdown can be easily identified.