基于NURBS和梯度法的飞艇形状优化

采用非一致有理样条曲线（NURBS）作为飞艇外形参数化方法、基于梯度的优化方法、飞艇体积作为约束条件、飞艇的阻力系数作为目标函数的优化流程对平流层流动条件下的飞艇外形进行了优化.阻力系数通过求解二维黏性不可压缩流场获得,阻力不但包含了形状阻力也包括了黏性阻力.优化过程以LOTTE飞艇的形状为初始形状,优化的结果表明优化...

Airship shape optimization with NURBS and gradient based algorithms

The present work attempts to conduct shape optimization of stratospheric airships with a method based on a combination of NURBS (non-uniform rational B-spline) and a gradient-based optimization algorithm.Drag coefficient was chosen as the objective function and airship volume as the constraint.NURBS based geometric parameterization was used because of its more efficient representation of the discrete geometric data than other methods (e .g. Bézier curve).Drag coefficient was obtained during the optimization iteration by solving two dimensional incompressible viscous flow field.Both form and viscous drags were considered when drag coefficient was calculated.Using LOTTE airship shape as initial shape,an improved shape with the above algorithm was obtained.Airship with the new shape obviously had better aerodynamic performance.It is eventually proved that the optimization method above can be effectively applied to airship optimization.