Shape optimization and experimental research of near space airship

Abstract

Shape optimization has important effects on drag reduction of the near-space airship. This paper uses the Bezier curve to parameterize the hull of the airship. Based on multiple island genetic algorithms, the optimization platform combined with different programs is established, and a kind of low drag hull is obtained by optimization. Force measurement and flow observation wind tunnel test are used to research the aerodynamic characteristics of the ellipsoid hull and the optimized hull. Results show that, optimization mainly increases the volume ratio and the favorable pressure gradient region of the hull, therefore the surface area is reduced and transition position of the hull can be delayed. Compared with the LOTTE shape, transition position of the optimized shape moved backward by 13.78%, and the volume drag coefficient is reduced by 11.1%. It is known from the wind tunnel test that compared with the ellipsoid hull, transition position of the optimized shape moves backward obviously. Under the condition that the volume Reynolds number is 2.97 × 106, compared with the ellipsoid hull, volume drag coefficient of the optimized shape can reduce by 39.0%.