Investigate on Dimension Effect of Dynamic Artificial Boundaries

The accuracy of numerical simulation for infinite field is relative not only to the principle of artificial boundary but also to the distance between boundary and initial perturbation source. Comparison and study of the dimensional effect of viscous boundary, transmitting boundary and viscous-spring boundary are carried out in this paper. Results show that, with the increment of the boundary dimensions of these boundaries, the calculation results get more and more close to the exact solution. When the boundary dimensions are increased to a certain degree, the results under these artificial boundary conditions are very close to each other. Moreover, the minimum distance meeting the accuracy requirement between the observation point and the artificial boundary is obtained. Results show that, the minimum distance is 1.5 times the size of wave source for viscous boundary, 0.75 times the size of wave source for viscous-spring boundary, and 1 times the size of wave source for transmitting boundary.