Simulation of Strongly Stratified Fluids
Stably and strongly stratified turbulent flows have been studied by employing scaling analysis of the governing equations along the lines of ,  and . The scaling analysis suggests the existence of two different dynamical states. The parameter determining the state is R = ReF h2, where Re and Fh are the Reynolds number and horizontal Froude number, respectively. If R ≫ 1, viscous forces are negligible and the turbulence is strongly anisotropic but three-dimensional and causes a forward energy cascade. The vertical length scale lv scales as lv ∼ U/N (U is a horizontal velocity scale and N is the Brunt-Väisälä frequency). If R ≪ 1, horizontal inertial forces are balanced by vertical viscous shearing and lv ∼ lhRe-1/2 (lh is a horizontal length scale). The scaling analysis has been confirmed by direct numerical simulations of homogeneous stratified turbulence. Spectra have been studied as well.
Keywordsstratification DNS turbulence geophysical flows
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- 8.Brethouwer G, Billant P, Lindborg E, Chomaz JM (2006) J Fluid Mech, submittedGoogle Scholar