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A coalescence model for freely decaying two-dimensional turbulence

Emmanuel Trizac
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Abstract

We propose a ballistic coalescence model (punctuated-Hamiltonian approach) mimicking the fusion of vortices in freely decaying two-dimensional turbulence. A temporal scaling behaviour is reached where the vortex density evolves like $t^{-ξ}$. A mean-field analytical argument yielding the approximation $ξ=4/5$ is shown to slightly overestimate the decay exponent $ξ$ whereas Molecular Dynamics simulations give $ξ=0.71\pm 0.01$, in agreement with recent laboratory experiments and simulations of Navier-Stokes equation.

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Emmanuel Trizac. 1998-08-18. A coalescence model for freely decaying two-dimensional turbulence. https://doi.org/10.1209/epl%2Fi1998-00415-5

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