The formation of new quasi-stationary vortex patterns from the interaction of two identical vortices in a rotating fluid
Within the framework of the quasi-geostrophic approximation, the interactions of two identical initially circular vortex patches are studied using the contour dynamics/surgery method. The cases of barotropic vortices and of vortices in the upper layer of a two-layer fluid are considered. Diagrams showing the end states of vortex interactions and, in particular, the new regime of vortex triplet formation are constructed for a wide range of external parameters. This paper shows that, in the nonlinear evolution of two such (like-signed) vortices, the filaments and vorticity fragments surrounding the merged vortex often collapse into satellite vortices. Therefore, the conditions for the formation and the quasi-steady motions of a new type of triplet-shaped vortex structure are obtained.
KeywordsVortex interaction Vortex merger Filamentation Triplet Quasi-Geostrophy
This is a contribution to PRC CNRS/RFBR 1069/16-55-150001. From the side of the MAS work was carried out within the framework of the state task no. 0149-2018-0001. This study receive support from Russian Foundation for Basic Research (Project No 16-05-00121), Russian Scientific Foundation (Project No. 14-50-00095), Ministry of Education and Science of Russian Federation (Project No. 14.W.03.31.0006).
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