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Vorticity filaments in two-dimensional turbulence: Creation, stability and effect. (English) Zbl 0910.76026

The formation, persistence, and effect of vorticity filaments are examined using a high resolution direct numerical simulation (DNS) of the merging of two positive Gaussian vortices pushed together by a weaker negative vortex. The authors come to the conclusion that the coherent vortex stabilizes the filaments. An asymptotic analysis and DNS for weak external strain show that a circular filament at a distance \(R\) from the vortex center always reduces the deformation of a Lamb’s (Gaussian) vortex in the region \(r\leq R\). The results are useful for the modeling of coherent and incoherent parts of two-dimensional flows.

MSC:

76F10 Shear flows and turbulence
76D99 Incompressible viscous fluids
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