Generation of Large-Scale Vorticity in a Homogeneous Turbulence with a Mean Velocity Shear

Abstract

An effect of a mean velocity shear on a turbulence and on the effective force which is determined by the gradient of Reynolds stresses is studied. Generation of a mean vorticity in a homogeneous incompressible turbulent flow with an imposed mean velocity shear due to an excitation of a large-scale instability is found. The instability is caused by a combined effect of the large-scale shear motions (''skew-induced" deflection of equilibrium mean vorticity) and ''Reynolds stress-induced" generation of perturbations of mean vorticity. Spatial characteristics, such as the minimum size of the growing perturbations and the size of perturbations with the maximum growth rate, are determined. This instability and the dynamics of the mean vorticity are associated with the Prandtl's turbulent secondary flows. This instability is similar to the mean-field magnetic dynamo instability. Astrophysical applications of the obtained results are discussed.

8 pages, 3 figures, REVTEX4, submitted to Phys. Rev. E

References in corpus (4)

• Formation of Large-Scale Semi-Organized Structures in Turbulent Convection
• Nonlinear Turbulent Magnetic Diffusion and Mean-Field Dynamo
• Anomalous and dimensional scaling in anisotropic turbulence
• Effect of Rotation on a Developed Turbulent Stratified Convection: the Hydrodynamic Helicity, the Alpha-Effect and the Effective Drift Velocity

Cited by in corpus (30)

• Magnetic diffusivity tensor and dynamo effects in rotating and shearing turbulence
• Generation of Magnetic Field by Combined Action of Turbulence and Shear
• Turbulent dynamos with shear and fractional helicity
• Numerical experiments on dynamo action in sheared and rotating turbulence
• Alpha effect and diffusivity in helical turbulence with shear
• Do mean-field dynamos in nonrotating turbulent shear-flows exist?
• Large-scale instability in a sheared nonhelical turbulence: formation of vortical structures
• Numerical study of large-scale vorticity generation in shear-flow turbulence
• Tangling clustering of inertial particles in stably stratified turbulence
• Pumping velocity in homogeneous helical turbulence with shear
• The supernova-regulated ISM. III. Generation of vorticity, helicity and mean flows
• Oscillatory large-scale dynamos from Cartesian convection simulations
• Calibrating passive scalar transport in shear-flow turbulence
• Enhancement of small-scale turbulent dynamo by large-scale shear
• Turbulent viscosity and effective magnetic Prandtl number from simulations of isotropically forced turbulence
• Angular momentum transport in convectively unstable shear flows
• Compressible test-field method and its application to shear dynamos
• Dynamo effect in unstirred self-gravitating turbulence
• Nonlinear shear-current dynamo and magnetic helicity transport in sheared turbulence
• Excitation of large-scale inertial waves in a rotating inhomogeneous turbulence
• On the existence of shear-current effects in magnetized burgulence
• On the shear-current effect: toward understanding why theories and simulations have mutually and separately conflicted
• Mixing at the external boundary of a submerged turbulent jet
• Generation of large-scale vorticity in rotating stratified turbulence with inhomogeneous helicity: mean-field theory
• Mean field dynamo action in shearing flows. II: fluctuating kinetic helicity with zero mean
• Sheared stably stratified turbulence and large-scale waves in a lid driven cavity
• Vorticity and magnetic dynamo from subsonic expansion waves
• Underlying mechanism of numerical instability in large eddy simulation of turbulent flows
• Generation of a large-scale vorticity in a fast rotating density stratified turbulence or turbulent convection
• Shear-driven magnetic buoyancy oscillations