APPLICATION OF THE E-EPSILON TURBULENCE CLOSURE-MODEL TO SEPARATED ATMOSPHERIC SURFACE-LAYER FLOWS

Citation
Ge. Liston et al., APPLICATION OF THE E-EPSILON TURBULENCE CLOSURE-MODEL TO SEPARATED ATMOSPHERIC SURFACE-LAYER FLOWS, Boundary - layer meteorology, 66(3), 1993, pp. 281-301
Citations number
43
Categorie Soggetti
Metereology & Atmospheric Sciences
ISSN journal
00068314
Volume
66
Issue
3
Year of publication
1993
Pages
281 - 301
Database
ISI
SICI code
0006-8314(1993)66:3<281:AOTETC>2.0.ZU;2-S
Abstract
Neutrally buoyant atmospheric surface-layer flow over a thin vertical wall has been studied using a turbulence closure scheme designed speci fically to address flow problems containing high shears. The turbulent flow model consists of a general solution of the time averaged, stead y state, two-dimensional Navier-Stokes equations, where the E-epsilon turbulence model has been used to close the system of equations. Model output compares favorably with measurements made in both a full-scale field study and in an atmospheric wind tunnel. In the simulation of f low over a solid wall, two recirculation eddies are produced. The smal lest eddy is located windward of the wall with a separation point loca ted at x/h = -0.8, and the largest is located in the lee of the wall a t x/h = 5.8. Immediately downwind of the wall top, the turbulent kinet ic energy, the energy dissipation rate, and the momentum flux all reac h a local maximum. These peak values generally maintain their height p osition z/h = 1.0, but decrease progressively downwind. The turbulent viscosity is strongly modified under the influence of the wall, with a local maximum forming in the lee of the wall top, and a local minimum forming at a height z/h = 2.0 above the lee recirculation eddy. The s urface momentum flux reduction due to the presence of the wall begins at x/h = - 10.0. Minimum zero fluxes occur at the surface separation p oints, and a local peak in momentum flux is produced at the centers of each recirculation eddy. Downwind of the wall, the modeled surface fl ux reaches an equilibrium at roughly x/h = 30.0.