A small disturbance in the strong vortex flow

A small disturbance in the axisymmetric, bathtub-like flow with strong vort icity is considered and the asymptotic representation of the solution is fo und. It is shown that if the disturbance is smaller than a certain critical scale, the conventional strong vortex approximation cannot describe the fi eld generated by the disturbance not only in the vicinity of the disturbanc e but also at the distances much larger than the critical scale. (C) 2001 A merican Institute of Physics.