Identification of Vortex Boundaries in Three-Dimensional Incompressible Flows Based on the Liutex-Shear Interaction

The traditional vortex identification methods identify the vortex boundaries by selecting arbitrary iso-surfaces without a clear theoretical base. It has been shown by Pang et al. that the residual shear has a strong dissipative effect on Liutex at the vortex boundaries in two-dimensional incompressible flows. Therefore, the vortex boundaries could be identified by these highly dissipative boundaries. The current paper aims to adopt the same procedure to three-dimensional (3D) incompressible flows (three-dimensional flow around the cylinder), and explore the possibility of defining 3D vortex boundaries in a similar manner.