引入虚面概念和虚拟分解算法,将多源面单目标面扫掠体(简称多源扫掠体)自动分解为多个单源面单目标面扫掠体(简称单源扫掠体).针对每个单源扫掠体,先生成虚面网格,然后生成包含虚面的单源扫掠体网格,以保证共享虚面上的网格一致性.单源扫掠体网格生成的关键是内点定位,通过改进仿射变换求解算法,解决了已有算法的2个缺陷,一是源面边界点共面时仿射函数不唯一,二是源面、目标面和扫掠路径弯曲时内部单元可能会扭曲.数值试验表明,新的内点定位算法在网格质量和执行效率上都要优于已有算法.与某商业软件扫掠网格生成结果的对比也验证了本文算法的实用性.
By means of virtual decomposition,a sweep volume with many sources and one target(many-to-one sweep volume) is automatically decomposed into several sub-volumes with only one source and one target(one-to-one sweep volume).Some artificial interfaces,called virtual surfaces,are automatically generated in the virtual decomposition process to seperate the neighboring sub-volumes.All the virtual surfaces are meshed by the projection method once before meshing the sub-volumes in order to maintain the conformity of the neighboring sub-volume meshes.For sub-volume mesh generation,how to locate interior nodes is the key,which is resolved by the affine mapping method.A new computing technique for the mapping function is proposed in this paper in order to overcome two drawbacks of the previous ones.One is that the mapping function is not unique when the boundary nodes of the source are coplanar.The other is that the interior elements may twist when the volume is composed of the curved source,target and sweeping path.It is demonstrated that the new location algorithm performs better than the other prevailing algorithms in terms of mesh quality and time efficiency.Finally,a comparison between the proposed hexahedral mesher and one commercial one is presented to verify the usability of the former.