|Program name||Package id||Status||Status date|
|Package ID||Orig. computer||Test computer|
|NESC9739/01||DEC VAX 11/780||DEC VAX 11/780|
2DFLOW is a vertically integrated dynamical drainage flow model developed from conservation equations for momentum and mass in a terrain following coordinate system. Wind fields from the dynamical model drive a Monte Carlo transport and diffusion model. The model needs only topographic data, an Eulerian or Lagrangian time scale, and a surface drag coefficient for input data; it can be started with a motionless atmosphere.
NEA-DB executed the test case included in this package on a VAX-11/780 computer in 8 minutes, 17 seconds of CPU time.
2DFLOW has the following features which make it attractive as a practical tool for estimating the concentrations of pollutants released into nocturnal drainage winds: 1) No wind or temperature data are needed. A surface drag coefficient and Eulerian or Lagrangian time scale are required, but the model is not sensitive to their exact value. High resolution topographic data are required. 2) The model has been successfully tested at sites with rugged mountainous terrain and at a site with gently rolling terrain. 3) The model is two-dimensional (vertically integrated) so its computational requirements are moderate. 4) Maximum pollutant concentrations are predicted to within factors of 2 to 10 at specific points, based on observed and simulated concentration time series.
|Package ID||Status date||Status|
|NESC9739/01||13-FEB-1987||Tested at NEADB|
|Package ID||Computer language|
VMS V4.3 (VAX-11/780).
|File name||File description||Records|
|NESC9739_01.002||2DFLOW Source Program||776|
|NESC9739_01.003||2DFLOW test case input data||20|
|NESC9739_01.004||2DFLOW topographical data library||59|
|NESC9739_01.005||2DFLOW sample output (concentrations data)||159|
|NESC9739_01.006||2DFLOW sample output (winds data)||289|
Keywords: Monte Carlo method, air pollution, diffusion, flow models, surface air, topography, turbulence, weather.