Drag reduction and shape optimization of airship bodies
Drag reduction and shape optimization of airship bodies
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DOI：
10.2514/6.1997-1483
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发表时间：
1997-06
期刊：
影响因子：
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通讯作者：
T. Lutz;S. Wagner
中科院分区：
文献类型：
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作者：
T. Lutz;S. Wagner
发展了一种用于不可压缩流场中零攻角轴对称体形状优化的数值计算工具。与通常的方法相反，该方法不以直接的方式优化身体的几何形状。相反，选择在机身轴线上的源分布来模拟机身外形和相应的无粘流场，源强度用作优化过程的设计变量。边界层计算是通过一个已证明的积分方法。为了确定转捩位置，采用了基于线性稳定性理论的半经验方法（e-n方法）。一个商用的混合优化器，以及与变异分布的协方差矩阵自适应的进化策略作为优化算法。针对不同雷诺数区域，对飞艇壳体进行了形状优化。目标是在给定的包线体积和规定的空速范围内使阻力最小
A tool for the numerical shape optimization of axisymmetric bodies submerged in incompressible flow at zero incidence has been developed. Contrary to the usual approach, the geometry of the body is not optimized in a direct way with this method. Instead, a source distribution on the body axis was chosen to model the body contour and the corresponding inviscid flowfield, with the source strengths being used as design variables for the optimization process. Boundary-layer calculation is performed by means of a proved integral method. To determine the transition location, a semiempirical method based on linear stability theory (e n method) was implemented. A commercially available hybrid optimizer as well as an evolution strategy with covariance matrix adaption of the mutation distribution are applied as optimization algorithms. Shape optimizations of airship hulls were performed for different Reynolds number regimes. The objective was to minimize the drag for a given volume of the envelope and a prescribed airspeed range