Relation between the quasi-cylindrical approximation and the critical classification for swirling flow

Abstract

It is shown that under the assumption of the quasi-cylindrical approximation with viscous effect the critical flow corresponds to a singularity, as flows approach the critical state from both sides, the radial components of velocity go separately to positive and negative infinity, and that for inviscid flow solution of the quasi-cylindrical approximation can only be trivial solution, i.e. strictly cylindrical flow. It is also shown that in subcritical range the iterative procedure accounting for non-linear effect of equations diverges necessarily.