open TELEMAC-MASCARET The mathematically superior suite of solvers

Dear all,

When we run the TELEMAC simulation, usually we will use the Courant number to check the simulation results are reasonable or not. But I am wonderly how could we know the reasonable value range for Courant number ?

and why we need to check the courant number ?

Hello,

Generally advection schemes are sensitive to Courant number, which is the number of elements crossed by the current in one time step. This is not really a problem in Telemac since all advection schemes are unconditionnally stable or do their own sub-stepping, except SUPG, but accuracy also depend on the Courant number. Small Courant numbers may also trigger too much numerical diffusion, this is why I favor a Courant number around 1. The number of iterations of solvers is also a hint to know if the problem is difficult or not.

With best regards,

Jean-Michel Hervouet

Thanks for this useful information.