open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello everyone
As indicated in the user manual of telemac2d, when handling control sections, the computation of fluxes have to be made in respect of continuity and should be compatible with the weak form of the impermeability condition. This can be done by activating the keyword COMPUTATION COMPATIBLE WITH FLUXES.

In the case of prescribed flowrates upstream, how doses telemac lead to wrong values of the usptream discharge since TELEMAC grab it from the liquid boundary file.
In my simulation, the upstream discharge is about 2092 m3/s but telemac2d give 1094 m3/s. This is realy strange,

Further, Fudaa give me a different result of discharge to the computed by using control sections with the respect of weak formulation of impermeability, however this is indicated in the user manual. Now, we have two results of flowrate, so which one is the more correct.

Please feal free to send me any explanation or kind of information, every post will be appreciated

Thank you in advance
Mourad

Dear Mourad,

Is it possible that your simulation hasn't reached a steady state and somehow flow is getting stored somewhere in your domain?

The differences from what Telemac outputs in control section and Fudaa
(or any other tool) for discharges are bound to the way that they are computed: Discrete integration of q, mean-velocity * area, Flux integration...

I've coded a few python scripts where I needed to calculate discharge at some sections and the values calculated using discrete integration taking into account velocity components (U and V, and implicitly the direction of the flow) which I consider an "appropiate" and somewhat easy to code procedure where really close to what Telemac output using the control Sections (a few 1E-2 differences)...In your case, if I needed to stick with a value of Q in a case of doubt I would choose Control's section one.

Regards,

José Díaz.