Energy- and flux-budget (EFB) turbulence closure model for stably stratified flows. Part I: steady-state,homogeneous regimes |
| |
| Authors: | S S Zilitinkevich T Elperin N Kleeorin I Rogachevskii |
| |
| Institution: | (1) Division of Atmospheric Sciences, University of Helsinki, Helsinki, Finland;(2) Finnish Meteorological Institute, Helsinki, Finland;(3) Nansen Environmental and Remote Sensing Centre, Bjerknes Centre for Climate Research, Bergen, Norway;(4) Pearlstone Center for Aeronautical Engineering Studies, Department of Mechanical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel |
| |
| Abstract: | We propose a new turbulence closure model based on the budget equations for the key second moments: turbulent kinetic and
potential energies: TKE and TPE (comprising the turbulent total energy: TTE = TKE + TPE) and vertical turbulent fluxes of
momentum and buoyancy (proportional to potential temperature). Besides the concept of TTE, we take into account the non-gradient
correction to the traditional buoyancy flux formulation. The proposed model permits the existence of turbulence at any gradient
Richardson number, Ri. Instead of the critical value of Richardson number separating—as is usually assumed—the turbulent and
the laminar regimes, the suggested model reveals a transitional interval,  , which separates two regimes of essentially different nature but both turbulent: strong turbulence at  ; and weak turbulence, capable of transporting momentum but much less efficient in transporting heat, at  . Predictions from this model are consistent with available data from atmospheric and laboratory experiments, direct numerical
simulation and large-eddy simulation. |
| |
| Keywords: | Anisotropy Critical Richardson number Eddy viscosity Heat conductivity Kinetic potential and total turbulent energies Stable stratification Turbulence closure Turbulent fluxes Turbulent length scale |
| 本文献已被 SpringerLink 等数据库收录！ |
|
