Nonstationary Vortex Streets in Shear Flows
- Authors: Kalashnik M.V.1,2, Chkhetiani O.G.1
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Affiliations:
- Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences
- NPO Taifun
- Issue: Vol 55, No 6 (2019)
- Pages: 602-611
- Section: Article
- URL: https://journals.rcsi.science/0001-4338/article/view/148749
- DOI: https://doi.org/10.1134/S0001433819060057
- ID: 148749
Cite item
Abstract
Spatially periodic vortex systems that form due to unstable shear flows are called vortex streets. A number of exact and asymptotic solutions of two-dimensional hydrodynamic equations describing nonstationary vortex streets have been constructed. It is shown that the superposition of the flow with a constant horizontal shear and its perturbations in the form of a nonmodal wave provides an exact solution that describes a nonstationary vortex street with rotating elliptic current lines. The width of the zone occupied by such a vortex street has been determined. The equation of separatrix separating vortex cells with closed current lines from an external meandering flow has been obtained. The influence of the quasi-two-dimensional compressibility and beta effect on the dynamics of vortex streets has been studied based on the potential vorticity transport equation. The solutions describing the formation of vortex streets during the development of an unstable zonal periodic flow and a free shear layer have been constructed using a longwave approximation.
About the authors
M. V. Kalashnik
Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences; NPO Taifun
Author for correspondence.
Email: kalashnik-obn@mail.ru
Russian Federation, Moscow, 109017; Obninsk, 249038
O. G. Chkhetiani
Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences
Author for correspondence.
Email: lgg@ifaran.ru
Russian Federation, Moscow, 109017