面向交界面网格的超网格算法研发及CFD应用

Research on Super-mesh Method for Grid-interface and its CFD Application

交界面网格是一种广泛应用于船舶CFD模拟的技术,其中网格间的插值算法是决定不同计算域之间流场信息传递精度的关键因素。论文面向船舶自航等复杂CFD模拟的应用需求,以开发交界面网格的高精度、守恒型插值算法为目的,开展超网格算法研究。介绍了超网格的概念和超网格算法的实现流程,包括贡献单元搜索与筛选、超网格生成、几种典型空间曲面交界面及其组合的处理及通量输运与重构方法。着重解决曲面交界面网格不共形的问题,以及圆柱形、圆锥形、圆台形及其组合体的超网格生成算法,并用典型分布函数测试和验证算法的精度和守恒性。对一艘散货船JBC船模开展了带与不带节能导管的自航CFD模拟和节能效果评估,与非守恒性插值算法模拟以及模型试验结果的对比表明,论文研究开发的超网格算法能有效提高自航模拟和节能效果评估的精度。

Interface-grid method is widely used in ship CFD simulation,in which interpolation algorithm is a key factor determining the precision of transferred flow field data between different regions.In this paper,research work on super-mesh method is carried out to develop an interpolation algorithm with high precision and fine conservation for interface-grid on account of the demand of complicated CFD simulation for ship self-propulsion.Connotation and basic concept of super-mesh is introduced briefly,and implementation procedure of super-mesh algorithm is presented including search of donor cell,construction of super-mesh,treatment of several typical curved interfaces and their combinations as well as methods of flux transportation and reconstruction.The method for solving non-conformal problem of curved interface-grid along with algorithm of super-mesh construction for cylinder,cone,frustum of cone and their combination is emphasized.Precision and conservation of super-mesh algorithm is tested and verified with typical distribution function.CFD simulations of a bulk carrier model named JBC with or without stern duct are carried out and the energy saving effect is evaluated.The results are compared with that from CFD simulations using non-conservative interpolation algorithm and the model test,and show that the super-mesh method developed in the paper can improve the precision of self-propulsion simulation as well as prediction of energy saving effect.