Engineering simulation method for three-dimensional wind field over complex terrains at low altitude

Based on the ellipsoid fitting method and the potential flow theory around sphere of aerodynamics, the paper proposes a new engineering simulation method and develops a systemic process, which could be applied to complex terrain including asymmetrical or symmetrical mountains. Firstly, a combining method of the least square method and the conformal mapping principle is presented and used to fit the ellipsoid from elevator data. Furthermore, using the potential flow theory, the mountain-induced airflow at low-altitude is carried out, by which the terrain's influence is characterized. Finally, the validity of this proposed method is verified in case study and numerical simulation. In this way, the combination of several mountains and the superposition of the corresponding mountain-induced airflow could provide wind field for the further research on terrain-tracking flight. The numerical analysis results indicate that the proposed method has characteristics of easy operation and higher accuracy and satisfying the engineering demands of flight dynamics.