open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello,

I get negatives concentrations at several points after 'CVDFTR' runs for one time step.

Does anyone has a clue from where it could comes from in CVDFTR?

Thank you in advance.

Regards.

Alexis

(PS: I am using V6P0)

Hello,

You can try an advection solver which ensures monotonicity (like 14). In fact this goes only with a coupling with telemac-2D, in which continuity is also strictly ensured (use CONTINUITY CORRECTION = YES, and in case of tidal flats use TREATMENT OF NEGATIVE DEPTHS = 2). Deposition is written in a way that prevents negative concentrations in the domain.

A lot of improvement has been done on these matters, especially to get an exact mass conservation of suspended sediment, in version 6.1.

With best regards,

Jean-Michel Hervouet

Jean-Michel,

It is not a matter of 'strict continuity' in my case. I get volume concentrations around -1!

Do you have any advice to depict where the trouble is?

I have difficulties to hand on the full advection-dispersion equation:
Where CS is initialized?

Sorry for bothering!

Alexis

Jean Michel,

When you say that "it goes only with a coupling with telemac2d" you mean an `on-line' coupling (i.e. at every time step)?

Thank in advance.

Alexis

Hello Alexis,

Yes, the algorithm needs to have the depths at the beginning and at the end of the time step that are compatible with velocities to ensure positivity of concentrations, it is only possible with a step by step online coupling.

With best regards,

Jean-Michel Hervouet