open TELEMAC-MASCARET The mathematically superior suite of solvers

Dear JMH

Attached is the fortran file that was used in the simulation

I am running a simple channel case, with no bathymetry applied to the model and no islands/hardlines etc. It puzzles me as how changing 1 small values could effect the models so much.

I would appreciate any feedback from you

Regards
Anas

Hello,

OK. I understand that the problem appears after some time. Most probably the free surface (plane 11) goes below plane number 10 at some location, is this possible ? This would be due to your forcing term, or to instability of the model. So again my question, what says subroutine calcot.f, what planes are intercrossing ? However when the free surface goes below another plane it is programmed that the plane will yield and stay below the free surface at some distance, so I doubt it is this problem, unless we have a bug here and you would be the first to face this situaton, in which case I would need the whole case to debug.

With best regards,

Jean-Michel Hervouet

Dear JMH

These are the error msg from calcot.f:

Calcot: LES PLANS 1 ET 2
SE CROISENT AU POINT 50685
COTE BASSE : 0.0000000000000
COTE HAUTE : -1.1564177703619842
DIFFERENCE : -1.1564177703619842
HAUTEUR : -6.3602977369909155

So the intersecting planes are between 1 and 2 (near the sea bed), instead of free surface plane. I have constructed variety of mesh to check if the problems are caused by the specific nodes on the geometry file, unfortunately they all still gave this error msg

Attached is the zip file for the model that I am running.

Many thanks
Anas





I also

Hello,

So what you get is quite normal, the depth becomes negative for some reason and it is no longer possible to build the mesh. Maybe your forcing term causes this. To go further you can configure your steering file as if you had tidal flats.

TIDAL FLATS = YES
OPTION FOR THE TREATMENT OF TIDAL FLATS : 1

but these 2 are normally the default, and :

TREATMENT OF NEGATIVE DEPTHS : 2

Then you can look where this problem occurs or where the depth becomes small. It may be a very temporary problem due to your initial conditions or due to the fact that your forcing term triggers a large wave.

With best regards,

Jean-Michel Hervouet