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采用梯度算法优化了平流层飞艇外形以减少气动阻力,目标函数飞艇总阻力系数通过求解Navier-Stokes方程获得.优化过程中采用了SSTκ-ω转捩湍流模型和Realizableκ-ε全湍流模型求解绕流流场,采用大涡模拟方法详细分析了获得的两种飞艇外形的气动性能和特点,并且比较了两种湍流模拟方法的流场求解对梯度法优化的目标函数以及飞艇形状特点的影响.结果表明:是否考虑转捩对优化的结果有明显的影响,考虑转捩优化方案的气动性能明显优于全湍流流动求解优化方案.采用转捩模型的优化由于层流区域的存在改变了飞艇尾部的形状,从而获得了尾部分离区较小的飞艇外形轮廓.
The gradient algorithm is used to optimize the shape of the airship to reduce the aerodynamic drag. The total drag coefficient of the target function airship is obtained by solving the Navier-Stokes equation. The SSTκ-ω turbulence model and the Realizableκ-ε turbulence model are used to solve the flow around the flow Flow field, the aerodynamic performance and characteristics of the obtained two kinds of airships were analyzed in detail by the method of large eddy simulation, and the effects of two kinds of turbulence simulation methods on the objective function and the shape characteristics of the airship were compared. Results It is shown that whether or not the transition is considered has a significant effect on the optimization results and the aerodynamic performance of the optimization scheme is considered to be significantly better than that of the full turbulent flow optimization solution.Optimization by transitional model changes the aft tail of the airship Shape, resulting in the tail separation area smaller airship contour.