Long time existence for a slightly perturbed vortex sheet

Russel Caflisch, Oscar F. Orellana

Research output: Contribution to journalArticle

Abstract

Consider a flat two‐dimensional vortex sheet perturbed initially by a small analytic disturbance. By a formal perturbation analysis, Moore derived an approximate differential equation for the evolution of the vortex sheet. We present a simplified derivation of Moore's approximate equation and analyze errors in the approximation. The result is used to prove existence of smooth solutions for long time. If the initial perturbation is of size ϵ and is analytic in a strip |ð�’¥m γ| < ρ, existence of a smooth solution of Birkhoff's equation is shown for time t < k2p, if ϵ is sufficiently small, with κ → 1 as ϵ → 0. For the particular case of sinusoidal data of wave length π and amplitude e, Moore's analysis and independent numerical results show singularity development at time tc = |log ϵ| + O(log|log ϵ|. Our results prove existence for t < κ|log ϵ|, if ϵ is sufficiently small, with k κ → 1 as ϵ → 0. Thus our existence results are nearly optimal.

Original languageEnglish (US)
Pages (from-to)807-838
Number of pages32
JournalCommunications on Pure and Applied Mathematics
Volume39
Issue number6
DOIs
StatePublished - 1986

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Vortex Sheet
Vortex flow
Smooth Solution
Existence Results
Differential equations
Formal Analysis
Perturbation Analysis
Wavelength
Strip
Disturbance
Singularity
Differential equation
Perturbation
Numerical Results
Approximation

ASJC Scopus subject areas

  • Mathematics(all)
  • Applied Mathematics

Cite this

Long time existence for a slightly perturbed vortex sheet. / Caflisch, Russel; Orellana, Oscar F.

In: Communications on Pure and Applied Mathematics, Vol. 39, No. 6, 1986, p. 807-838.

Research output: Contribution to journalArticle

Caflisch, Russel ; Orellana, Oscar F. / Long time existence for a slightly perturbed vortex sheet. In: Communications on Pure and Applied Mathematics. 1986 ; Vol. 39, No. 6. pp. 807-838.
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