Resolving unsteady micro-scale atmospheric flows by nesting a CFD simulation into wide range numerical weather prediction models |
| |
| Authors: | Simon Schneiderbauer Stefan Pirker |
| |
| Affiliation: | 1. Institute of Fluid Mechanics and Heat Transfer, Johannes Kepler University , Altenbergerstr. 69, Linz, Austria simon.schneiderbauer@jku.at;3. Christian-Doppler Laboratory on Particulate Flow Modelling , Institute of Fluid Mechanics and Heat Transfer, Johannes Kepler University , Altenbergerstr. 69, Linz, Austria |
| |
| Abstract: | The open boundary conditions for the CFD simulation of the micro- and meso-scale flow and temperature distribution around the Grimming mountain, Austria, are determined by an optimisation approach from interior observations. The numerical weather prediction model ALADIN–Austria provides wind speed and wind direction at those spatially arbitrarily defined observations. Furthermore, the plausibility of the resulting flow over the Grimming mountain is checked (a) by data of a ground station at the top of the Grimming mountain showing suitable correlation with the measurements. Besides, (b) the vertical turbulence profiles at the ground station are qualitatively compared to extensive studies covering the Askervein hill. In addition, (c) the wavelength of internal gravity waves obtained from the numerical CFD model is examined by analytic approximations at the Grimming mountain and by linear mountain wave theory at a mathematically idealised hill. Finally, the grid independence of the presented CFD model is shown. |
| |
| Keywords: | open boundary conditions optimisation approach unsteady mirco-scale atmospheric flow CFD RNG k–? turbulence model ALADIN-Austria Numerical weather prediction (NWP) |
|
|
