TY - JOUR

T1 - Stabilizing and destabilizing effects of a solid-body rotation on quasi-two-dimensional shear layers

AU - Lesieur, Marcel

AU - Yanase, Shinichiro

AU - Métais, Olivier

PY - 1991/1/1

Y1 - 1991/1/1

N2 - The effect of a solid-body rotation, characterized by an angular velocity Ω, on a two-dimensional mixing layer (in a plane perpendicular to Ω) of relative vorticity ω2D, upon which is superposed a small three-dimensional turbulent perturbation, is considered. Using the Kelvin theorem in the frame rotating with il, and with the aid of arguments based on the straining of absolute vortex filaments by the basic velocity, it is shown that the rotation is always stabilizing (with respect to the nonrotating case) in the cyclonic case. In the anticyclonic case, a slight rotation is destabilizing. At a local Rossby number R0 = |ω2D|/ 2|Ω| of the order of 1, the anticyclonic rotation disrupts catastrophically the coherent structures of the mixing layer. Anticyclonic rotation becomes stabilizing again for R0 <0.5. Also presented are three-dimensional numerical simulations which support the theory, and agree qualitatively with experimental results. The consequences for oceanic and atmospheric vortices are briefly discussed.

AB - The effect of a solid-body rotation, characterized by an angular velocity Ω, on a two-dimensional mixing layer (in a plane perpendicular to Ω) of relative vorticity ω2D, upon which is superposed a small three-dimensional turbulent perturbation, is considered. Using the Kelvin theorem in the frame rotating with il, and with the aid of arguments based on the straining of absolute vortex filaments by the basic velocity, it is shown that the rotation is always stabilizing (with respect to the nonrotating case) in the cyclonic case. In the anticyclonic case, a slight rotation is destabilizing. At a local Rossby number R0 = |ω2D|/ 2|Ω| of the order of 1, the anticyclonic rotation disrupts catastrophically the coherent structures of the mixing layer. Anticyclonic rotation becomes stabilizing again for R0 <0.5. Also presented are three-dimensional numerical simulations which support the theory, and agree qualitatively with experimental results. The consequences for oceanic and atmospheric vortices are briefly discussed.

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U2 - 10.1063/1.858149

DO - 10.1063/1.858149

M3 - Article

AN - SCOPUS:0010259065

VL - 3

SP - 403

EP - 407

JO - Physics of fluids. A, Fluid dynamics

JF - Physics of fluids. A, Fluid dynamics

SN - 0899-8213

IS - 3

ER -