Reappraisal of Whitham's 1967 theory for wave-meanflow interaction in shallow water

被引:4
作者
Bridges, Thomas J. [1 ]
Ratliff, Daniel J. [2 ]
机构
[1] Univ Surrey, Dept Math, Guildford GU2 7XH, England
[2] Northumbria Univ, Dept Math Phys & Elect Engn, Newcastle Upon Tyne NE1 8ST, England
关键词
Whitham modulation theory; Benjamin-Feir instability; Coalescing characteristics; Stokes waves; Wave-mean flow interaction; FINITE-AMPLITUDE; GRAVITY-WAVES; DEEP-WATER; INSTABILITY; MODULATION; PACKETS;
D O I
10.1016/j.wavemoti.2022.103050
中图分类号
O42 [声学];
学科分类号
070206 ; 082403 ;
摘要
The modulation equations for Stokes waves in shallow water coupled to wave-generated meanflow, derived in Whitham (1967), based on an averaged Lagrangian are re-visited. Firstly, it is shown that they can be recast into two coupled classical shallow water equations, with modified gravity having the sign of the Whitham index: sign(omega 0 ''omega 2). Secondly, it is shown that the amplitude of the meanflow and amplitude of the wave are, in general, independent. Thirdly, the implications of the coalescing characteristics, whose unfolding is associated with the Benjamin-Feir instability, are studied.(c) 2022 Published by Elsevier B.V.
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页数:14
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