Global time evolution of viscous vortex rings

福本, 康秀

説明

This article gives an overview of growing knowledge of translation speed of an axisymmetric vortex ring, with focus on the influence of viscosity. Helmholtz-Lamb's method provides a short-cut to manipulate the translation speed at both small and large Reynolds numbers, for a vortex ring starting from an infinitely thin core. The resulting asymptotics significantly improve Saffman's formula (1970) and give closer lower and upper bounds on translation speed in an early stage. At large Reynolds numbers, Kelvin-Benjamin's kinematic variational principle achieves a further simplification. At small Reynolds numbers, the whole life of a vortex ring is available from the vorticity obeying the Stokes equations, which is closely fitted, over a long time, by Saffman's second formula.

収録刊行物

MI Preprint Series

MI Preprint Series 2009-1 2009-01-16

Faculty of Mathematics, Kyushu University

キーワード

詳細情報詳細情報について

CRID: 1050861482659342464

HANDLE: 2324/13203

本文言語コード: en

資料種別: journal article

データソース種別

IRDB

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