Kelvin waves with helical Beltrami flow structure

In this work we show that when an inviscid axisymmetric Rankine flow experiences a soft expansion, rotating Kelvin waves can be excited. Downstream of the region where the expansion occurs (the transition region) the resulting flow can be expressed as the addition of a Rankine and a Beltrami flow. T...

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Bibliographic Details
Authors: González, R., Sarasua, G., Costa, A.
Format: article
Status:Published version
Publication Date:2008
Country:Argentina
Institution:Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
Repository:Biblioteca Digital (UBA-FCEN)
Language:English
OAI Identifier:paperaa:paper_10706631_v20_n2_p_Gonzalez
Online Access:http://hdl.handle.net/20.500.12110/paper_10706631_v20_n2_p_Gonzalez
Access Level:Open access
Keyword:Boundary conditions
Flow structure
Rotational flow
Beltrami constant
Beltrami flow
Kelvin wave
Oscillatory flow
Rankine flow
Fluid dynamics
Description
Summary:In this work we show that when an inviscid axisymmetric Rankine flow experiences a soft expansion, rotating Kelvin waves can be excited. Downstream of the region where the expansion occurs (the transition region) the resulting flow can be expressed as the addition of a Rankine and a Beltrami flow. The Beltrami constant is determined from the Rankine upstream flow, and the helix pitch of the n=1 mode results from the boundary conditions downstream. Finally, a discussion of the process leading to oscillatory flow and a conjecture about the topological background that sustains the Beltrami flow structure are offered. © 2008 American Institute of Physics.