Rortex based velocity gradient tensor decomposition

Abstract

Recently, a vector named Rortex was proposed to represent the local fluid rotation [C. Liu et al., “Rortex—A new vortex vector definition and vorticity tensor and vector decompositions,” Phys. Fluids 30, 035103 (2018)]. In this paper, a universal Rortex based velocity gradient tensor decomposition is proposed and the relevant local velocity increment decomposition is provided. Vortex structures in boundary layer transition on a flat plate are analyzed to quantify the local rotational, compression-stretching, and shearing effects. The results demonstrate that vorticity is shearing-dominant, while the rotational part or Rortex in general occupies a small part of vorticity in most areas of this case. In other words, vorticity is a quality representing shearing rather than rotation or vortex in most regions of this case.

Document Details

Document Type
Pub Defense Publication
Publication Date
Jan 01, 2019
Source ID
10.1063/1.5084739

Entities

People

  • Chaoqun Liu
  • Yisheng Gao

Organizations

  • Air Force Office of Scientific Research
  • University of Texas at Arlington

Tags

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Computer Vision.
  • Fluid Dynamics.