Accession Number : ADP002266

Title :   Waves on Vortex Cores and Their Relation to Vortex Breakdown,

Corporate Author : GRENOBLE UNIV (FRANCE)

Personal Author(s) : Maxworthy,T. ; Mory,M. ; Hopfinger,E. J.

Report Date : JUL 1983

Pagination or Media Count : 13

Abstract : It was conjectured by Hopfinger, Brown and and Gagne (1982), (1) that traveling, large amplitude 'kink' waves, observed by them in rotating, turbulent fluid might be at the origin of vortex breakdown and small scale turbulence production. This observation motivated us to study such waves experimentally on isolated vortices under controlled conditions. Their characteristics are interpreted in terms of theories based on the localised induction equation. It is found that these kink waves remain stable and exhibit soliton interaction properties. Axisymmetirc travelling waves on the contrary cause breakdown when their amplitude exceeds a certain magnitude. Benjamin's (1967), (2) theory was used to calculate the critical phase speed and the velocity perturbation inside a wave of finite amplitude. The theoretical results show that the axial velocity changes rapidly become large so that, according to instablity considerations, growth of spiral disturbances is possible. Breakdown caused by axisymmetric waves and possibly by combined, axisymmetric and kink waves, is demonstrated experimentally. (Author)

Descriptors :   *Vortices, *Flow fields, Turbulent flow, Stability, Velocity, Waveforms, Interactions, Potential flow, Flow visualization

Distribution Statement : APPROVED FOR PUBLIC RELEASE