Circulation Conserved Diffusion Vortex Method
摘要
A new vortex method is proposed for two-dimensional incompressible viscous flows. The method is based on a use of the so-called diffusion velocity and remains completely Lagrangian (grid-free). The original diffusion vortex method (Ogami and Akamatsu, 1991 [1]) and its modified versions (Shintani and Akamatsu, 1994 [2]) are questioned and corrected in a way such that the circulation is truly conserved as it should be when convected at both the fluid velocity and the diffusion velocity. This new method is not claimed better due to its low computational efficiency but claimed to be the physically accurate one. It is also shown analytically that the core expansion rate in the present method is a little slower than that of the core expansion scheme (Leonard, 1980 [3]), and thus the resolution can be expected to be higher, when the ratio of the distance between neighboring particles to the core size of the vortex particles is less than 1.13.