open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello,

Recently I added salinity to my hydrodynamics model in order to account for density effect in the estuary. However, abnormal values appears after first several time steps only at three points in the shallow/dry area. Other nodes have logical values. Does anyone have this kind of problem in your simulation?

Hello,

Please check that you use :

TIDAL FLATS : YES
OPTION FOR THE TREATMENT OF TIDAL FLATS : 1
TREATMENT OF NEGATIVE DEPTHS : 2
SCHEME FOR ADVECTION OF TRACERS : 13

It will give you a conservative advection of tracers, with monotonicity, that should do it.

With best regards,

Jean-Michel Hervouet

Thanks! I used the same options except SCHEME FOR ADVECTION OF TRACERS = 14 in my model. I'll try to use 13 instead.

Hello,

I run the model with new numerical options but I got abnormal salinity values again after 5 time steps in the same area.

I have another finer mesh for this model and in the same area I didn't find the abnormal values. Does it have something to do with the grid size?

Hello,

So it is doubtful it makes any change with option 14. It should have nothing to do with the grid size. If you send your case I can have a look at it and see if we have this problem with another compiler and/or with the future 6.2 version.

JMH

Hello,

It has a little change with option 13, it makes abnormal values less abnormal but they're still abnormal...

You can download this case at
dl.dropbox.com/u/47298319/Scheldt_Model_...0_3D_Salinity.tar.gz

Thanks for your help!

Hello,

OK, the access is denied from EDF here, but I'll get it from my home. Allow me time to look at this case, so if you can live with the finer mesh for some time...

JMH

That's no problem. Thanks again!

Hello,

I tested running the case with different SCHEME FOR ADVECTION OF TRACERS and I found option 1 works well and give salinity values between -1.85 to 32.0 which are better then option 13 and 14. If I change both SCHEMES FOR ADVECTION OF VELOCITIES AND K-EPSILON to 1, it gives salinity values between -1.05E-05 to 32.0.

It seems the SCHEME FOR ADVECTION caused those abnormal values but I don't know why. Hope this helps.

Hello,

Option 1 is the method of characteristics, it is unconditionally stable and monotonous, but not mass conservative. I like it for advecting the velocities.

JMH