Wind field simulation using adaptive tetrahedral meshes

Abstract

In the finite element simulation of environmental processes that occur in a three-dimensional domain defined over an irregular terrain, a mesh generator capable of adapting itself to the topographic characteristics and to the numerical solution is essential. The objective of this work is to present our recent results in these topics. An unstructured adaptive tetrahedral mesh of a region bounded on its lower part by the terrain and on its upper part by a horizontal plane is constructed. In this automatic mesh generator, a simultaneous untangling and smoothing procedure to optimise the resulting mesh has been introduced. Once the adapted mesh has been constructed in accordance with the geometrical characteristics of the domain, an adaptive local refinement is used in order to improve the numerical solution of a mass consistent wind field model. Air pollution models usually start from the computation of this velocity field. In this paper, a model for computing such a field based on the contribution of the observed wind flow and the vertical buoyancy or momentum plume rise defined by a Gaussian plume model is summarized. All these techniques are applied to real and test problems.