Study of Hybrid Air Vehicle Stability Using Computational Fluid Dynamics

This paper uses computational fluid dynamics to predict aerodynamic damping of airships or hybrid air vehicles. This class of aircraft is characterized by large lifting bodies combining buoyancy and circulatory lift. Damping is investigated via forced oscillations of the vehicle in pitch and yaw. The employed method is verified using data for lighter-than-air vehicles. The use of fins and stabilizers is found to be beneficial. The rear part of the body is dominated by separated flow that contains more frequencies than the forcing frequency imposed on the body. The final design is seen to be dynamically stable across a range of conditions for small pitch angles.