Abstract
Numerical simulations are performed to investigate the characteristics of the formation of alternate and multiple bars with the use of the NHSED2D model. The results of the simulations show reasonably good agreement with the results of the theoretical analysis and the experiments. It is found that periodic boundary conditions with an insufficiently small calculation domain tend to stabilize multiple bars. It is also found that there is possibility that different initial configurations lead to different equilibrium states. The reduction of the bar mode can be well explained by the theoretical results that the difference between the dominant modes associated with the maximum growth rate and the maximum equilibrium amplitude. The irregularity appeared in the reduction process of the bar mode is suggested to be caused by the nonlinear interaction between multiple modes of bars.
