Extended Abstract (432K)J2.5
Pressure, vorticity and vortices associated with scalar microfronts in a large-eddy simulation of Canopy Flow
Li Fitzmaurice, University of California, Davis, CA; and R. H. Shaw, K. T. Paw U, and E. G. Patton
Turbulence within and above a vegetation canopy flow is simulated using large-eddy simulation (LES). Pressure is calculated in the LES by solving a Poisson equation. Vorticity is derived from the three-dimensional velocity fields. Vortices are identified based on the pressure and the vorticity. Tilted Scalar microfronts, which features high scalar concentration gradient, are observed in the LES. Where a scalar microfront occurs, a high-pressure region is centered at the intersection of the scalar microfront and the canopy top. In the vicinity of the high-pressure regions, there exist sausage-like elongated low-pressure and high vorticity tubes, which indicate vortices. Most of the tubes tilt downstream with height. The relation between the sausage-like elongated vortices and the scalar microfronts is casual and inconsistent.
Joint Session 2, Dispersion (Joint with the Fourth Symp. Urban Environment, 12th Joint Conf. on the Applications of Air Pollution Meteorology with A&WMA, and 25th Conf. Agricultural & Forest Meterology)
Tuesday, 21 May 2002, 1:30 PM-4:40 PM
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