open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi,

I want to model a domain with a debit imposed by a river but I'm blocked at the initial conditions.
If I puts nothing, no calculation happens!!! Error!
If I impose a water depth on the edge nodes liquid, I have, after 35 seconds of calculation done right, the following message :

ill-posed problem, clearance on border with incoming velocity, supercritical flow ....

Je suis presque sûr que mon écoulement n'est pas torrentiel, vu la faiblesse du débit, et d'ailleurs j'ai ce message quelque soit le débit imposé!

Could you help me with this?

Je précise que j'ai imposé un débit sur le bord liquide avec un profil de vitesse constant (choix 1)

Hello,

The problem is that to find the velocity that will ensure a given discharge, the program needs a depth which is not 0 (else the velocity will be infinite). If you start by prescribing a small depth the program will start with a high velocity, which may lead to supercritical flow. If you cannot give initial conditions that ensure at once to have a fluvial flow, a possible solution is to extend your domain upstream with a zone with lower bottom that can be filled with water in the initial conditions, or you put a lower bottom in the first row of elements, so that the flow is always fluvial.

Another possibility is to prescribe both velocity and depth to start with, with a depth not no far from what you expect in the end, then you can relax the depth.

With best regards,

Jean-Michel Hervouet

Hi,

Thank you very much!! you are deblocked my situation..

Your sincerly