the train with a volume of air around it, as illustrated inFigure 5. For overset meshing to be successful, there issufficient overlap between background and componentregions. Overset interfaces are created in the overlappingsurfaces to connect the background zone and componentFigure 5. Overview of overset mesh.zone by interpolating cell data in the overlapping boundary condition. A moving coordinate system is establishedin the component region to create the motion of the trainand meanwhile, the overset interfaces coming from overlapping in subdomain are continually updated with themoving train.