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ANALYTIC SOLUTIONS FOR LONG INTERNAL WAVE MODELS WITH IMPROVED NONLINEARITY. Alexey Slunyaev Insitute of Applied Physics RAS Nizhny Novgorod, Russia. 2-layer fluid rigid-lid boundary condition Boussinesq approximation. 1. 2. Representation in Riemann invariants.
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ANALYTIC SOLUTIONS FOR LONG INTERNAL WAVE MODELS WITH IMPROVED NONLINEARITY Alexey Slunyaev Insitute of Applied Physics RAS Nizhny Novgorod, Russia
2-layer fluid rigid-lid boundary conditionBoussinesq approximation
1 2
Representation inRiemann invariants [Baines, 1995;Lyapidevsky & Teshukov 2000;Slunyaev et al, 2003] 2-layer fluid rigid-lid boundary conditionBoussinesq approximation
The fully nonlinear (but dispersiveless) model The full nonlinear velocity [Slunyaev et al, 2003; Grue & Ostrovsky, 2003]
Velocity profiles h = 0.5 h = 0.1 clin u1 clin u2 u2 2 V+ 1 2 V+ u1 1
The full nonlinear velocity asymptotic expansions for any-order nonlinear coefficients
2-layer fluid rigid-lid boundary conditionBoussinesq approximation The full nonlinear velocity Exact relation for H1 = H2 Corresponds to the Gardner eq
Exact fully nonlinear velocity for asymp eqs Exact velocity fields (hydraulic approx) Strongly nonlinear wave steepening (dispersionless approx) The GE is exact when the layers have equal depths
stratified fluid free surface condition Rigorous way for obtaining asymptotic eqs
stratified fluid free surface condition Rigorous way for obtaining asymptotic eqs extGE
Asymptotical integrability (Marchant&Smyth, Fokas&Liu 1996) KdV 2nd order KdV
GE Almost asymptotical integrability extGE
GE Almost asymptotical integrability extGE
GE Almost asymptotical integrability extGE
2-order GE theory as perturbations of the GE solutions Qualitative closeness of the GE and its extensions
GE Initial Problem AKNS approach
GE AKNS approach mKdV AKNS approach
GE mKdV
GE AKNS approach mKdV
mKdV GE a – is an arbitrary number
GE Tasks: Passing through a turning point? = (t)
GE Tasks: Passing through a turning point? = (t) A solitary-like wave over a long-scale wave
GE A solitary-like wave over a long-scale wave
GE+ mKdV+ discrete eigenvalues may become continuous a a soliton cannot pass through a too high wave being a soliton
GE+ mKdV+ soliton amplitude (s denotes polarity) Solitons soliton velocity
GE- mKdV- at the turning point all spectrum becomes continuous
GE- mKdV- soliton amplitude soliton velocity
This approach was applied to the NLS eq The initial conditions: an envelope soliton and a plane wave background periodical boundary conditions periodical boundary conditions an envelope soliton plane wave plane wave
This approach was applied to the NLS eq NLS “breather” Spatio-temporal evolution envelope soliton
Solitary wave dynamics on pedestals may be interpreted Strong change of waves may be predicted (“turning” points)
Co-authors Gavrilyuk S. Grimshaw R. Pelinovsky E. Pelinovsky D. Polukhina O. Talipova T. Thank you for attention!