open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi all,

I have a couple of questions:

1) I want to calibrate on the free surface.I imagine this would rule out 'CONSTANT DEPTH/ELEVATION' as options for the INITIAL CONDITIONS. As such I'm using ZERO ELEVATION. My inlet has prescribed discharge and a prescribed elevation. Despite doing this I keep getting the error message:

DEBIMP_3D: PROBLEM ON BOUNDARY NUMBER #
GIVE A VELOCITY PROFILE
IN THE BOUNDARY CONDITIONS FILE
OR CHECK THE WATER DEPTHS
OTHER POSSIBLE CAUSE:
SUPERCRITICAL ENTRANCE WITH FREE DEPTH

I thought prescribing the elevation would prevent the above message in order to prevent super-critical flow entering a dry domain. Obviously I've misinterpreted something somewhere but I'm not sure what.

If I'm prescribing Q at the inlet and want to calibrate the free surface, is the ZERO ELEVATION wrong to use?

2)When a TELEMAC 3D finishes a run with a high time step I frequently receive the error message "TELEMEC 3D failed to export [results file]".

Why would this occur? My time step is already quite low and I have sufficient memory on the system.

Thanks,
Simon

Dear Simon,

Caveats: I'm a newbie telemac user and this will possibly be a nonsense answer to the first question.

Each time i start a "cold start" simulation in telemac2D using a prescribed steady inlet flow and a prescribed constant elevation output (to generate a "steady" hotstart for the real simulation) in Fudaa-Prepro i enable "Intial conditions" and give a positive and reasonable "FREE SURFACE" elevation along the inlet boundary, so telemac has some water to move.

I assume this procedure is taken by telemac2d/3D as a "suggestion" rather than an imposed condition (because the real imposed condition is the flow magnitude), so generally in the output file this free surface is different, and i asume this one the "appropriate one" to start the real (unsteady) simulation.

I also remember reading somewhere in Fudaa options that having a "prescribed elevation" and a "prescribed flowrate" at the same time in a boundary condition is not "yet" implemented (over constrained system maybe?).

I hope someone with more knowledge of the telemac system can properly answer this post...

Regards,

José.