非结构动网格下非定常气动力计算和嗡鸣研究

【作者】 史爱明；

【导师】 杨永年；

【作者基本信息】 西北工业大学 ， 流体力学， 2003， 硕士

【摘要】 本文主要进行了非结构运动网格技术的研究，并采用了全隐式双时间的时间离散方法和格心格式空间离散的中心有限体积法对二维翼型和三维机翼以及翼身组合体的非定常流场进行了数值模拟；并结合基于非结构运动网格技术的非定常流场解算器研究了舵面的跨音速单自由度颤振——“嗡鸣”。 在非结构运动网格技术方面，本文发展了一种适用于解决非定常气动力计算的、高效的、鲁棒性较好的非结构运动网格方法。在现有的经典线性弹簧方法的基础上，通过对网格单元边、面和体的考虑，引入了对线性弹簧倔强系数诸如抗拉、抗扭和抗压等多种修正方法。在计算量增加不多的情况下，大大的提高了非结构运动网格的适应性，具有一定的工程实用价值。 在流场求解技术方面，本文在时间推进上采用全隐式的双时间推进方法；在空间上采用格心格式的有限体积法对非定常Euler方程进行空间离散，用四步Runge—Kutta方法作显式的拟时间推进，同时采用当地时间步长、隐式残值光顺等加速收敛措施；求解了二维亚、跨、超音速的非定常流场和三维无后掠机翼、M6机翼、翼身组合体的非定常流场。非定常流场的计算结果与实验结果符合的很好说明本文非定常流场计算正确，非结构运动网格可靠、鲁棒性好。 在气动弹性问题方面，本文采用能量法分析和研究了嗡鸣。从非定常流场计算出发系统的研究了嗡鸣发生的机理以及扰流片对嗡鸣起抑制作用的机理；应用能量法确定了嗡鸣发生的边界；并且研究了机翼舵面之间有隔膜和无隔膜以及机翼上有上翼扰流片和无上翼扰流片对嗡鸣发生边界的影响；得出了有意义的结论。更多还原

【Abstract】 In the dissertation, the unstructured dynamic mesh technique is investigated. Full implicit dual-time temporal derivatives and cell-center finite volume method spatial derivatives are adopted to simulate unsteady flow fields of 2-D airfoil, 3-D wing and wing-body configuration. Transonic single-freedom flutter of flap-buzz is studied with the unsteady flow field solver of the unstructured dynamic grid technique.An effective and well robust unstructured dynamic grid method is developed to solve the unsteady aerodynamic problem. On the basis of classic linear spring analogy, several modified methods for the linear spring stiffness coefficient is introduced. These methods take into account segments, facets and bodies of the cell, In the case of not much penalty in computing, the adaptation of the unstructured dynamic mesh is greater enhanced.In the paper, 2-D and 3-D unsteady flow fields are computed. The results of solving the unsteady flow fields that are in agreement with the experiments show that the unsteady flow field solver is correct and the unstructured dynamic mesh technique of the dissertation is well robust. So the unsteady flow field solver can be applied to various kinds of problems with moving and deforming bodies.In the thesis, an energy analysis method is applied to study the buzz. Through solving the unsteady flow fields of an airfoil-flap, the mechanism of buzz is intensively studied. On the basis of the unsteady flow fields of an airfoil-flap with an upper-wing spoiler, the mechanism of the upper-wing spoiler suppressing the buzz is researched. In additions, the comparisons of the unsteady flow fields of an airfoil-flap with and without a separator show that the separator reduce the speed of the buzz.更多还原