Direct consequences stem from the close relation between the recently proposed vortex vector (Rortex) and the swirling strength. It is shown that these vortex-identification methods share some relevant properties: (i) both provide the same and, practically, the largest vortex region, (ii) both allow an unlimited uniaxial stretching described by an axisymmetric strain rate, so the strain-rate magnitude inside a vortex may become much larger (without any limitation) than the vorticity magnitude, and (iii) both exhibit a discontinuous outcome, known as the so-called disappearing vortex problem.
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