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Hi

interesting question,
I'm not sure you can, as you need to re-interpolate the results from the coarse to the new mesh.

Via Matlab it's certainly possible, with some tweaking (so far I'm not using Matlab with v4, haven't found the need , yet ;).

Often I interpret manually my preliminary results to apply them as initial conditions with simple functional relations (1st order equations or simple slopes)

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Good luck
Ivar

This is quite easily done with the new model builder in v4+ of COMSOL. There may be simpler and better ways to do it than what I do, but I like my method because I can understand what I have. One of the beautiful features of finite-element methods, is that mapping coarse solutions onto finer mesh solutions is straight forward because each point in space is interpolated (by definition) within the nodes of the finite element ! I am stating this procedure from memory, so please excuse me if I make a mistake !

1. after the coarse mesh solution is obtained, I save the model file

2. then I right click on the "solver" block of the model builder and choose "copy"

3. a copy node is then created just down the tree from the right-click point

4. right click on the copy node, and rename it to something you can recognize; for example, "coarse-mesh converged solution"

5. create a 2nd finer mesh, by first right-clicking on mesh, create mesh-2. I typically rename most every node in the model builder tree to something I can recognize.

6. in the solver portion, under the solver step, set the mesh to the new mesh

7. in the dependent variables section, specify the initial conditions (two places, also variables not solved for) as coming from the solution, and then below that pick your newly saved copy called "coarse-mesh converged solution:.

8. after setting everything else like you want, right click on the solver, and pick "compute"

Like I said earlier, there may be an easier way (for example, using the "continue" feature), but I like this because I can understand what I am doing this way. The current solved solution is typically called "solution 1", so I am copying "solution 1" to a separate place. Then if I mess up, or my next solution attempt fails, I have not lost the good converged solution from the coarse mesh. You can also verify the interpolated coarse-to-fine mesh initial condition by plotting the initial conditions in the results portion of the tree to be sure it is what you want.

Hi James

THanks for an interesting and useful procedure, I'll certainly use that one ;)

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Good luck
Ivar

Hi James,

this helped me, too. Thank you.

Stefan