Three-Dimensional Transition of the Vorticity Created by an Impacting Water Drop
A falling water drop impacting the free surface of a pool of water creates approximately circularly symmetric vorticity. This vorticity rolls up into a primary vortex ring and undergoes a transition to a three-dimensional structure. Under certain conditions this characteristic large-scale structure is strikingly similar to an above-ground atomic blastc The range of parameters discussed here is of interest because the resulting vorticity is at a Reynolds number very near the transition Reynolds number, therefore the flow goes from laminar to turbulent to laminar again, allowing careful study of the transition process. The nature of the instability is discussed with particular regard to categorization. It is suggested that it is not the Widnall instability that is initially at work, although it may play a role at later times.
KeywordsVortex Ring Primary Ring Vortex Line Vortex Sheet Vortex Filament
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