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
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.