Point-Vortex Approach in Two-Dimensional Turbulence
| Autor: | B. N. Kuvshinov, T. J. Schep |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Physics
Physics and Astronomy (miscellaneous) Turbulence Vorticity Condensed Matter Physics 01 natural sciences 010305 fluids & plasmas Vortex Dipole symbols.namesake Classical mechanics Condensed Matter::Superconductivity Vortex stretching 0103 physical sciences symbols Exponent Symplectic integrator 010306 general physics Hamiltonian (quantum mechanics) |
| Zdroj: | Физика плазмы. 42:535-548 |
| ISSN: | 0367-2921 |
| DOI: | 10.7868/s0367292116050061 |
| Popis: | The properties of two-dimensional turbulence in a circular domain are investigated within the framework of the punctuated point-vortex model. Vortex dynamics is governed by Hamiltonian equations, and it is interrupted by instantaneous events resulting in vortex merging. Motion of about 100 point vortices is simulated using an accurate, symplectic integration method. Ensembles of like-sign vortices relax to a quasi-lattice state. Vortices with zero total vorticity tend to be randomized. Their motion still does not become fully chaotic. We observe emergence of long lived large dipoles (co-propagating pairs of vortices with opposite signs), which affect the evolution of the whole vortex ensemble. The presence of such dipoles accelerate the vortex decay rate. The decay exponent has been estimated as ξ ≃ 1.7, which is much larger than ξ ≃ 0.7, reported in previous studies of decaying turbulence. Since dipole dynamics depends on specific properties of the point vortex system, our findings suggest that a universal decay exponent in such systems does not exist. |
| Databáze: | OpenAIRE |
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