Master of Science (MS)
First Committee Member
Darrell W. Pepper
Number of Pages
A 3-dimensional model that calculates windfields over irregular terrain based on meteorological tower data has been developed. The governing equations of atmospheric motion, the finite element method and atmospheric boundary layer concept have been introduced. A surface model of the Nevada Test Site (NTS) has been generated from DEM files which contain elevation data, and a 3-D mesh has been generated. Initial estimates of the velocity field are developed by interpolating surface and upper level wind measurements. A diagnostic objective analysis technique is used to generate 3-D winds above the surface layer. This algorithm incorporates NTS tower field measurements to initialize and generate the upper level windfield. A surface boundary layer technique is used to calculate the upper level windfield. Vertical velocities are developed from successive solutions of the continuity equation, followed by an iterative procedure which reduces divergence over the complete field; The finite element method is used to solve a Poisson equation which is used to adjust the velocity components. The upper and lateral boundaries above the topography are assumed to be open, allowing mass flow through the boundaries. The bottom boundary is set by the topographic elevations of NTS region, and is assumed to be solid. Major advantages of the procedure are that it is computationally efficient and allows boundary values to adjust in response to changes in the interior flow. The method has been successfully tested using a 3-D cavity problem and using NTS field measurements. The correctness of this method was verified by testing 3-D cavity model. Results from NTS model were compared with the Mathew diagnostic model used by Lawrence Livermore National Laboratory (LLNL). The influence of windfield by tower data was also discussed. The NTS model formulation can readily be extended to include other relevant physical and dynamic solution constraints such as momentum and energy conservation.
Assessment; Diagnostic; Dimensional; Element; Finite; Model; Three; Windfield
Mechanical engineering; Civil engineering; Environmental sciences
University of Nevada, Las Vegas
Shi, Zijiang, "A three-dimensional finite element model for diagnostic windfield assessment" (1996). UNLV Retrospective Theses & Dissertations. 3258.