YinYangZhong grid: An overset grid system for a sphere
For numerical simulations inside a sphere, an overset grid system, YinYangZhong grid, is proposed. The YinYangZhong grid is an extension of the YinYang grid, which is widely used in various simulations in spherical shell geometry. The YinYang grid is itself an overset grid system with two component grids, and a new component grid called Zhong is placed at the center of the YinYang grid. The Zhong grid component is constructed on Cartesian coordinates. Parallelization is intrinsically embedded in the YinYangZhong grid system because the Zhong grid points are defined with cuboid blocks that are decomposed domains for parallelization. The computational efficiency approaches the optimum as the process number increases. Quantitative test simulations are performed for a diffusion problem in a sphere with the YinYangZhong grid. Correct decay rates are obtained by the simulations. Two other tests in magnetohydrodynamics (MHD) in a sphere are also performed. One is an MHD dynamo simulation, and the other is an MHD relaxation simulation in a sphere.
sphere yinyang grid magnetohydrodynamics overset grid method