Energy- and flux-budget (EFB) turbulence closure model for stably stratified flows. Part I: steady-state, homogeneous regimes

TittelEnergy- and flux-budget (EFB) turbulence closure model for stably stratified flows. Part I: steady-state, homogeneous regimes
PublikasjonstypeBook Chapter
Utgivelseår2007
ForfattereZilitinkevich, S, Elperin, T, Kleeorin, N, Rogachevskii, I
Refereed DesignationUnknown
RedaktørBaklanov, A, Grisogono, B
BoktittelAtmospheric Boundary Layers: Nature, Theory and Applications to Environmental Modelling and Security
Antall sider11-35
UtgiverSpringer Science+Business Media B.V
ISBN-nummer9780387743189
NøkkelordAnisotropy, Critical Richardson number, Eddy viscosity, Heat conductivity, Kinetic, potential and total turbulent energies, Stable stratification, Turbulence closure, Turbulent fluxes, Turbulent length scale
Sammendrag

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, 0.1 < Ri < 1, which separates two regimes of essentially different nature but both turbulent: strong turbulence at Ri ≪ 1; and weak turbulence, capable of transporting momentum but much less efficient in transporting heat, at Ri > 1. Predictions from this model are con- sistent with available data from atmospheric and laboratory experiments, direct numerical simulation and large-eddy simulation.

URLhttp://www.springerlink.com.pva.uib.no/content/h813u00q9x3j2726/
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