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This paper explores the stability of vortical structures in fluids, particularly focusing on the tripole vortex observed in the Bay of Biscay through laboratory experiments. A semi-analytical solution is provided to describe the flow patterns and vorticity cross-sections of the tripole, consisting of a core vortex and two satellite vortices (n=2). The study also examines quadrupole and pentapole configurations and utilizes concepts like the point-vortex model, Stock’s theorem, and Hamiltonian dynamics to analyze the dynamical behavior and stability of these vortex formations.
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2D vortices in fluids:Stability of vortical ensembles Ziv Kizner
Pingree & Le Cann, 1992 Tripole eddy observed in the Bay of Biscay
Lab experiment Semi-analytical solution Flow pattern Vorticity cross sections Tripole:A core vortex & two (n = 2) satellites core satellite
Quadrupole, n = 3 Vorticity cross section core satellite
L r = R Point-vortex concept Stock’s theorem: v D L Point vortex: r
y B b rA,B rB,C A a rA,C c C x Tripole: -1 2 -1 Point-vortex ensemble: Autonomic dynamical system
-1 y B B l A A +2 l C C tripole troika -1 x Stability of a point-vortex tripole • Invariants of a troika • Impulse: • Hamiltonian: 2.Tripole 3.Tripole stability On the iso-Hamiltonian sheet Impulse: troika = tripole Hamiltonian: the tripole supplies a minimum to P2 monotonic function of l
Tripole oscillator y y y y y y y y
The end פרופ' זיו קיזנר: ziv.kizner@gmail.com 03-531 8790 משרד: