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为开展非线性气动弹性研究,基于非线性结构有限元软件NASTRAN和自主研制的多块结构化计算流体力学(CFD)求解器,开发了一套基于计算流体力学/计算结构动力学(CFD/CSD)耦合求解方法的气动弹性时域仿真程序。该程序采用径向基函数(RBF)交换两套求解器之间的数据并进行网格变形。为提高RBF方法的效率,构造了基于多次插值的空间待插值点精简算法。在多次插值过程中,每次插值的对象为上次插值的误差,并同时限制插值区域,以此实现了空间待插值网格数的精简。数个网格变形的算例表明该方法可支持大变形运动,并且具有较高的计算效率。采用此程序开展了AGARD 445.6机翼颤振计算、大展弦比机翼的静气动弹性计算与切尖三角翼极限环振荡(LCO)现象的动气动弹性仿真,结果揭示了当机翼展弦比较大或者响应幅值较大时,结构非线性对于气动弹性有显著影响。
In order to carry out nonlinear aeroelasticity research, a set of CFD solvers based on non-linear finite element software NASTRAN and self-developed software were developed. Based on the computational fluid dynamics / computational structural dynamics (CFD / CSD) ) Aeroelastic Time Domain Simulation Program for Coupling Solution. The program uses Radial Basis Function (RBF) to exchange data between two sets of solvers and to deform the mesh. In order to improve the efficiency of RBF method, a spatial interpolation algorithm based on multiple interpolation is proposed. In the process of multiple interpolation, the object of each interpolation is the error of the last interpolation, and at the same time, the interpolation area is limited. In this way, the number of spaces to be interpolated is reduced. Numerical examples of several mesh deformations show that this method can support large deformations and has high computational efficiency. Using this program, the dynamic aeroelastic simulation of AGARD 445.6 wing flutter calculation, large aerosymmetric wing aerostatic elasticity calculation and cutting edge delta wing limit cycle oscillation (LCO) was carried out. The results show that when the wing strings When the amplitude is large or the response amplitude is large, the structural nonlinearity has a significant effect on aeroelasticity.