Dynamic Wind Field Simulation and Efficiency Analysis Over 3D Terrain Based on the Lagrangian Method

Abstract

A method for simulating a three-dimensional wind field is proposed in which a graphics engine is used together with some feature data from CFD (computational fluid dynamics) calculations. First, important data such as DEM (digital elevation model), wind speed and wind direction data are extracted from the CFD output file. Combined with data that may represent the characteristics of wind, including wind speeds, wind directions, grid unit wind direction vectors and unit vectors normal to the topography, the wind properties of each grid are derived. Then, the organization mode of the terrain grid is optimized based on the OSG (OpenSceneGraph) graphics engine. Furthermore, multithreading tasks load the segmented terrain maps and generate the texture. The main thread renders all the generated textures in batches according to the index file and synthesizes the whole terrain. In this way, the nodes of the wind field are set up and modified according to the properties of the corresponding grids. Finally, the Euler and Lagrangian methods are applied to describe the wind field features: the former describes the velocity and direction of each point in the field at a certain time, while the latter is adopted to continuously represent the changes in the velocity and direction of a particle. Experimental results show that the FPS (frames per second) value is within a reasonable range and can still meet the real-time requirements of rendering as the research area expands. INDEX TERMS CFD, DEM, OSG, rapid topographic construction, Euler wind field, Lagrangian wind field.