open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi,
I have run a telemac2d case with Finite volume(ROE SCHEME),there are large area of tidal flat in my domain,I also set the VARIABLE TIME-STEP to YES, but after some steps,the listing file shows warning of NEGATIVE WATER DEPTH and the time step become very small(1e-2 second),means it will take lots of time to finish my case.I wonder if there are some unreasonable setup in my cas file ,attachment are my cas file ,hope you can help me,thank you.
Besides,the version of telemac2d are v7p3r0,and some setup of tidal flats are show below.
TIDAL FLATS = YES
OPTION FOR THE TREATMENT OF TIDAL FLATS = 2
TREATMENT OF NEGATIVE DEPTHS = 2
MINIMUM VALUE OF DEPTH = 0.1

liuy

Hello

What is known, is that the Roe scheme is not entropic and thus it does not conserve positivity of water depth. Instead use scheme 1 or 5 (kinetic or HLLC).
These are options for finite volumes, which are more costly than finite elements.
If you want to use finite elements, you have to comment the keyword EQAUTIONS
and you have to use scheme 13 or 14. See user manual (section tidal flats) for more explanations.

with my best regards

Riadh