Analysis of hybrid air vehicles using computational fluid dynamics

This paper presents a study of the aerodynamics of shapes pertinent to lighter-than-air vehicles, using computational fluid dynamics. The work begins with the validation of the computational-fluid-dynamics method using a 6:1 prolate spheroid. The validated method is then employed for the study of the flow around a shape similar to the Airlander 50 airship of Hybrid Air Vehicles Ltd. An overview of the flow around this kind of shape is presented, supported by pressure survey, flow visualisation and transition effects, as function of the Reynolds number. The sensitivity of the transition location to the Reynolds number is also demonstrated, and then, the role of each component of the vehicle is analysed. The effect of each component on the flow-field, the lift and drag, and stability in pitch are provided. It was found that the fins contributed the most to increase the lift and drag coefficients