An Improved Mass Consistent Model for Three-Dimensional Wind Field Construction

Abstract

An improved diagnostic mass-consistent finite element model (FEM) has been developed to construct 3D wind fields over irregular terrain. Instead of using constant Gauss precision moduli over the whole domain in the existing mass-consistent models, the improved mass-consistent model adopts different Gauss precision moduli based on the terrain topography gradient associated with atmospheric boundary conditions. These terrain sensitive moduli resolve wind flows over large topographical obstacles more accurately than constant Gauss precision moduli. In this study, a terrain following mesh generator is developed based on digital elevation data from the U.S. Geological Survey, and the data linked to the modified mass-consistent FEM model. The improved model is validated and verified using a benchmark study for flow over a semicylinder. The model is then used to re-examine 3D wind fields previously simulated for the Nellis Dunes area near Las Vegas, NV. Results show that the improved mass consistent modeling system shows better agreement with the recorded meteorological tower data than the previous results obtained using constant moduli.