网格对声爆近场预测影响的数值研究

Numerical Investigation of Influence of Mesh Property in Nearfield Sonic Boom Prediction

为研究网格对近场声爆预测结果的影响,使用自研的基于非结构混合网格的三维RANS(reynolds average navier-stokes)求解器对典型标模的近场声爆过压分布进行了数值模拟和分析。以双锥旋成体模型和69°后掠三角翼模型(69°delta wing body,DWB)为考核算例,以风洞测量结果为参考,分别研究了网格对齐方式、网格类型和网格分布等因素对声爆近场过压预测的影响。结果表明网格面沿马赫角对齐对声爆预测结果捕捉有显著的改善效果,模型附近采用圆柱区域包裹的结构和非结构网格均能很好的捕捉声爆近场过压分布,但非结构网格由于可以快速生成,应用更为方便。网格展弦比和马赫锥面周向网格间距对流场中激波峰值和激波形状的捕捉有明显影响,使用相对合理的网格展弦比和马赫锥面周向网格间距有利于提高近场声爆预测精度。最后,将总结的网格生成策略应用于洛马公司LM1021(lockheed-martin 1021-01 configuration)全机构型的近场声爆预测,验证了其实用性。

To investigate the influence of mesh property in nearfield sonic boom prediction,the over-pressures of several typical configurations are commutated and analyzed with an in-house Reynolds Average Navier-Stokes solver.The property of mesh alignment,mesh type and mesh distribution are analyzed based on the double cone configuration and the 69-degree Delta Wing Body configuration.The experimental data from wind tunnel are used as comparisons.The results show that the Mach cone aligned method has significant improvement to the accuracy for the prediction of sonic boom in nearfield.Both structured and un-structed mesh with a cylinder zone near the model can help to capture the distribution of the over-pressure,however,it is more convenient to use unstructured mesh when deal with complex configurations.The aspect ratio and circumferential spacing affect the captured shock wave peak value and the shapes.The accuracy of the prediction can be satisfied by carefully selecting these two factors.In the last,the summarized strategies for mesh generation are applied in the sonic boom prediction of a complex supersonic transport configuration,the Lockheed Martin 1021 to verify its practicability.