open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello, everyone! I am simulating a perfectly still settling basin containing water with an initial uniform sediment concentration.

The result is not good enough. My problem is that the plane of sediment concentration is not very flat while I think it should be flat. I have tried many parameters but they don't change too much.

Can anyone tell me what causes this kind of problem? Or it is just natural?

Great thx!

Hi
How are the plane?
Maybe you should attach in your topic all the file used in your problem (in a zip in order to avoid problems)

regards

The planes of sediment concentration are not parallel and flat, while I think they should be.

Here is my complete file but a little bit big. So I divide them into two groups. Thx for your help!

Hello,

This is probably not totally natural as I suppose that you would expect to get the same pattern as the bottom variations, but numerically it may depend on the unstructured mesh. Since probably all functions are not linear you have some finite element approximations in the result and these approximations do not necessarily follow the bottom topography pattern.

With best regards,

Jean-Michel Hervouet

Thx for your reply. If I set the parameter 'scheme for advection of tracers' as 0, the planes of sediment concentration are totally straight no matter when. But I don't think we should set this value like that in this case. So it is a little bit strange for me.

Is there any possibility that they will be flat if we use different solvers and schemes? But up to now, I haven't got a very good solution.

Thx for your help!

Hello,

This is strange, scheme 0 removes the advection, then nothing should happen except diffusion, so well, scheme 0 is not something to do though it could be that settling velocity is still activated in this case (it is treated differently than the other velocities).

Regards,

JMH