Optimal shape design of an airship based on geometrical aerodynamic parameters

Abstract

BackgroundConventional airship mathematical modeling usually involves six coupled degrees of freedom and two inputs, namely tail and thrust. The current study focuses on aerodynamic modeling. The aerodynamic model is developed in 3D-space based on plane semi-empirical model of a symmetric airship. The model depends on the main geometrical parameters of the airship. The study introduces an optimal shape design of the airship. The objective function is established to reduce drag and the effect of side flow and increases both lift force and pitching moment. Three types of airship shape construction are investigated, namely NPL, GNVR, and Wang.ResultsMATLAB genetic algorithm toolbox is used to obtain the optimal shape. The population size is 50 and the number of generations is also 50 for NPL, GNVR and Wang shapes at each corresponding angle of attack (alpha =left[ -20^circ ,20^circ right] ) and side-slip angle (beta =left[ -20^circ ,20^circ right] ). The shapes are compared to select the best fit within the operating range. To get the optimal shape, weighted averaging is performed on the optimal solution.ConclusionThe GNVR geometric construction technique is the best method to generate the optimum shape of the airship in the presence of side-slip angle effect with the utilized objective function that reduces drag and side flow and increases lift and pitching moment.