open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello,

I use telemac to simulate a river. The total flow rate is very high (Q=26400m³/s) and there are areas where the froude number is close to 1 or superior to 1. In these areas, I have stability problem.

I would like to know if there is a way to improve the stability .

(increase eddy viscosity, choose a particular turbulence model, etc...)

(change options in solveur, ...)

I put a word document with pictures and the cas file inside.

Thanks

Stéphane

Hello,

Your parameter file is very basic, I would first try the option with wave equation :

TRAITEMENT DU SYSTEME LINEAIRE : 2
SOLVEUR : 1

and look at the test case called Malpasset and inspire from its parameter file (implicitation coefficients, mass-lumping)

then the best way to avoid wiggles is now to use:

COMPATIBILITE DU GRADIENT DE SURFACE LIBRE : 0.9

(default is 1)

If it is not enough you can go down to 0.

The Froude number is not a problem, you have to look at the Courant number : U*DT/DX.

Other thing, I would not take a diffusion coefficient of 10. Try 1. instead.

I hope something will help among all this,

Jean-Michel Hervouet

Thank you, I will try what you said. And I will let you know the results

Stephane

Hi,

I used the option "traitement du systeme lineaire" with value equal 2 (résolution de l'équation d'onde) and it worked pretty well as shown on the picture attached !

Thanks again.

Stephane