open TELEMAC-MASCARET The mathematically superior suite of solvers

Merry Christmas everyone. I was hoping to get this model working so that I could have a relaxing day with the kids but I'm having problems with mass balance. I'm simulating the flow through a series of tight 180 degree turns. I can get a converged solution but my outflow is about 25 % less than my inflow. I've played around with all sorts of boundary conditions/ different solvers/ different turbulence models but I haven't been able to get mass balance. If anyone could offer any suggestions I would be very grateful.
Thanks and Happy New Year!

Hello Stephen,

To have a chance to see an exact mass balance, you need to have the keyword:

CONTINUITY CORRECTION : YES

in your steering file. It must be so because at your exit the continuity equation is replaced by the equation prescribing the elevation, so the exiting flux computed with the velocities at the exit may not be compatible with continuity. CONTINUITY CORRECTION forces the compatibility.

You will find a mass balance of the order of magnitude of the accuracy asked for propagation. Then if you use TREATMENT OF NEGATIVE DEPTHS = 2 you will find the accuracy of the machine, because this options recomputes the continuity in an exact way.

With best regards,

Jean-Michel Hervouet