Three-dimensional simulation of flow over complex terrains at low altitude

Simulation of flow field over mountains usually plays an important role in atmospheric dynamics and engineering application, and some of its modeling methods are reviewed in this paper. Aiming at studying the flight dynamics of fixed wing vehicles passing through complex terrains, an engineering and three-dimensional (3D) simulation method based on potential fluid theory is modified in this paper. Based upon the theory of flow around a sphere, the flow field over any 3D complex terrain composed of Gaussian-shaped mountains, each with the same slop along the streamwise and spanwise directions, is simulated. Besides, the spherical center and radius will be determined by applying particle swarm optimization algorithm. Furthermore, the theory of flow around an ellipsoid is used to model the wind field over any Gaussian-shaped mountain with different slops. Finally, the flow field over an arbitrary Gaussian-shaped terrain is simulated and analyzed. The method in this paper can supply real-time flight simulation with 3D wind velocity field over complex terrains.