Enhanced Visualization of Late Stage Transitional Structures using Vortex Identi cation and Automatic Feature Extraction

The unsteady Navier Stokes equations o er a large variety of instantaneous solutions even for rather simple boundary conditions once the rel evant spatial and temporal scales of the problem at hand are adequately resolved This is especially true for DNS Direct Numerical Simulation of laminar turbulent transition where an initially lam inar ow disturbed by some unsteady uctuations breaks down into small scale high frequency tur bulence When trying to study and understand this process one faces the problem of identifying the rel evant structures to describe the ow which consist of vortices and shear layers and on their isolation for further investigation Here we present a post processing method based on the vortex de nition proposed by Jeong Hussain and on Feature Extraction similar to Silver that allows to suc cessfully identify isolate and track vortical features in a transitional boundary layer