open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi all,

We are French engineer students, and we are currently running an hydrologic model of a pond in telemac2d. Our model requires the following meteorological data : wind and rainfall (or evaporation).
But if we consider the wind and rainfall/evaporation, the free surface elevation is not physical and increase dramatically.
It seems that this problem is a bug of telemac2d, and is probably due to the combination of several factors : tidal flats, wind and rainfall/evaporation.
We manage to reproduce this problem/bug with a simple case. Our simplified files are attached.
Note that the shape (elevation, size) of the mesh can be modified easily thanks to the file princi.f
Many factors seem to have an influence on this inconsistent raising of the free surface, and the figure below shows for example to what extend the wind (along Y) can change the results.



The value of the initial elevation of the free surface has be fixed at +1m in order to have tidal flats. The Rain-Evaporation is constant and is egal to -50 mm/day, that is why the final elevation (after 10 days) should be +0.5m.

Is there a solution to avoid this problem? Is this bug already known?

Regards,
Thank you for your interest
Luc, Sebastien, Paolo & Laurent

Hello,

This will be solved in the next version and is due to the fact that you have slightly negative depths in your domain when the wind blows(to avoid this you can use the option : TREATMENT OF NEGATIVE DEPTH = 2). Another way to fix the problem is to update subroutine prosou.f in library telemac-2D (or preferably take it into your fortran file) and in the second line after the word TENTATIVELY, change HN%R(I) into MAX(HN%R(I),0.D0). The problem came from the fact that the procedure limiting evaporation on dry zones did not take into account the fact that depth could be slightly negative in some options.

Regards,

Jean-Michel Hervouet

Thank you for your answer, and the solutions you gave us to solve this problem.
Best regards