Discussion Forum

Hello,

I am a very new to COMSOL and want to build up a 3D model with motion in EM field by v4.1.

Now I meet some problems. The solver is Time Dependent solver.

1. Time step

My model needs stop by finishing each single step and then remesh. For example, there are 3 steps at time 0, 0.5 and 1. When the step at 0 is finished, the solver is stop and remesh for time 0.5. However, I found the mesh is still on the position of 0. One way I used to deal with this is run two time steps(0,0.5) each time so the remesh will work at time 0.5. Then I restart the solver at time 0.5 with the initial as the solution of (0, 0.5), but this double the running time of the model. Is this method correct or is there any other way to do this?

2.Stop condition

As I want to stop at each step, my stop condition is this
StartTime+StepSize+adj-t
where adj is a number smaller than StepSize.
This stop condition works not well. It stops the solver at the time I expect but sometimes the last time step is disappear. For example, when the solver is stop at time 0.5234256, the solution at time 0.5 doesn't come out. Where is the problem and is there any other reliable way to approach this?

3.Convergence

I found the solver is hard to converge when use moving mesh. How to deal with this and is there anyone can support me some documents on this problem?

Thank you for reading.

Yan Jiang