Abstract
A finite-volume code (SWIFT) has been developed at the University of Surrey to compute flow and dispersion in stably-stratified flow over topography. An advanced pressure-correction algorithm is used to solve the incompressible flow equations on a terrain-following curvilinear grid. Turbulent transport is represented by a two-equation eddy-viscosity model using a length-scale-limiting strategy suitable for atmospheric boundary-layer applications.
A detailed simulation is undertaken of one particular case-study hour in the Cinder Cone Butte dispersion experiment and concentrations compared with field and laboratory data. Flow-field calculations are consistent with strongly-stratified flow forced to move in horizontal planes around the base of the hill, although the calculated “dividing-streamline height” is an overestimate of the depth of this layer. Plumes from upwind sources exhibit a strong sensitivity to wind direction, in good agreement with towing-tank simulations. A number of assumptions widely used in regulatory dispersion models are found to be invalid.
A detailed simulation is undertaken of one particular case-study hour in the Cinder Cone Butte dispersion experiment and concentrations compared with field and laboratory data. Flow-field calculations are consistent with strongly-stratified flow forced to move in horizontal planes around the base of the hill, although the calculated “dividing-streamline height” is an overestimate of the depth of this layer. Plumes from upwind sources exhibit a strong sensitivity to wind direction, in good agreement with towing-tank simulations. A number of assumptions widely used in regulatory dispersion models are found to be invalid.
| Original language | English |
|---|---|
| Pages (from-to) | 1059-1071 |
| Number of pages | 13 |
| Journal | Atmospheric Environment |
| Volume | 31 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - Apr 1997 |
Keywords
- atmospheric diffusion
- complex terrain
- computational fluid dynamics
- stable stratification