[Wenjun]

Hi, everyone! I want to simulate a wave solution which shapes are shown in the figures at t=0s, t=1s and t=3s. I tried the periodic boundary condition as well as the Dirichlet boundary condition, however, they both didn't work. Can anyone tell me which kind BC should I choose? Thanks very much!

[FMDenaro]

Originally Posted by Wenjun

Hi, everyone! I want to simulate a wave solution which shapes are shown in the figures at t=0s, t=1s and t=3s. I tried the periodic boundary condition as well as the Dirichlet boundary condition, however, they both didn't work. Can anyone tell me which kind BC should I choose? Thanks very much!

You should indicate what model you are solving! Linear o non-linear 1d wave equation? However, for both models the periodic BC are suitable, the difference is that the first simply produce a rigid translation of the initial function, the Burgers equation wil produce expansion/shock. The characteristic lines propagate the value from the initial state so that you can simply build an exact solution

[Wenjun]

Originally Posted by FMDenaro

You should indicate what model you are solving! Linear o non-linear 1d wave equation? However, for both models the periodic BC are suitable, the difference is that the first simply produce a rigid translation of the initial function, the Burgers equation wil produce expansion/shock. The characteristic lines propagate the value from the initial state so that you can simply build an exact solution

Hi, Thank you for your kind reply. My equation is the nonlinear Schrodinger equation. When I use the periodic BC, there appears oscillation in the boundary. The oscillation then propagates to the center of the wave. By the way, the wave doesn't move to the left or right. It only moves up and down. But the solution is exactly a smooth even function. Maybe this initial date is a little special such that we need some special BC to deal with it. But I don't know which one can work yet. Seek for help!