Numerical Aerodynamic and Design Analysis of Combined Saucer-Shaped Buoyancy-Lifting Airships

Saucer-shaped buoyancy-lifting airships have attracted worldwide attention due to their huge potential for stratospheric platform and cost-effective operation, especially in large load transportation. Combined saucer-shaped airship is a high-altitude, maneuverable, high buoyancy efficiency lighter-than-air (LTA) vehicle for providing continuous communications and surveillance capabilities over a wide geographical area. In this work, combined saucer-shaped airships are designed different in thickness-to-radius ratio but the same in semi-major axis. Based on the Reynolds-averaged N-S equations and k-ω SST turbulent model, numerical aerodynamic investigations on combined saucer-shaped stratospheric airships are conducted to confirm the influence of thickness-to-radius ratio on the aerodynamic forces, stability, and payloads. It is found that with the increased of thickness-to-radius ratio, the volume-to-area ratio increases, and the positive lift at the negative angles and the static instability in pitching channel is improved, while the positive lift at the positive attack angles and the lift-to-drag ratio decrease, and drag is significantly enhanced. That means the larger the thickness-to-radius ratio, the more the payload, but the worse the aerodynamic characteristic. The airship B, with the thickness-to-radius ratios of 1/2, provides average performance in buoyancy efficiency and drag characteristics. This investigation serves to provide reasonable reference for new concept design of load airships.