Compressibility Effect in Vortex Identification

摘要

Summing up, from the most popular vortex-identification schemes (Q, △, λ_2, and λ_(ci)), only the △ criterion and the associated λ_(ci) criterion are extendable to compressible flows. Both criteria fulfill a specific condition that is conveniently expressed for compressible flows in terms of the invariants of the deviatoric part of ▽u by the form of Eq. (10).