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在旋转坐标系下,将Spalart-Allmaras(S-A)一方程湍流模型和Reynolds-averaged NavierStokes(RANS)方程耦合成一个新的RANS方程,并发展了基于多块重叠网格的强耦合RANS求解方法,用于直升机旋翼悬停流场的数值模拟.为了提高计算效率,针对多重网格方法在多块重叠网格上实施的困难,提出了一种基于重叠网格的多重网格实施方法.通过对Caradonna-Tung(C-T)和ONERA 7A旋翼悬停算例验证了发展的强耦合RANS方法和基于重叠网格的多重网格实施方法的有效性.研究结果表明:发展的基于重叠网格的多重网格方法有较高的计算效率,3层网格的加速比约为7.7;强耦合RANS法的计算精度明显高于传统的松耦合RANS方法,特别是在与阻力相关性能参数的预测中,强耦合RANS方法的预测结果更加精确.
The Spalart-Allmaras (SA) one-equation turbulence model and the Reynolds-averaged NavierStokes (RANS) equations are coupled into a new RANS equation in a rotating coordinate system, and a strongly coupled RANS solution based on multiple overlapping grids is developed. For the numerical simulation of helicopter rotor hover flow field.In order to improve the computational efficiency, aiming at the difficulty of multi-grid method implemented on multiple overlapping grids, a multigrid-based grid implementation method is proposed. The Caradonna-Tung (CT) and ONERA 7A rotor hovering examples demonstrate the effectiveness of the developed strongly coupled RANS method and the multigrid-based multigrid implementation approach. The results show that the developed multigrid-based multigrid Grid method has higher computational efficiency, and the speedup ratio of three-layer grid is about 7.7. The calculation accuracy of the strongly coupled RANS method is obviously higher than that of the traditional loosely coupled RANS method, especially in the prediction of resistance-related performance parameters The result of the coupled RANS method is more accurate.