Dear all,

I am using the pressure-based coupled solver. This pressure-velocity coupling method requires input of the Courant number. the default value in FLUENT is 200. I think i need to lower this value for better convergence. Any idea how to select a proper value?

Best regards, Woo

P.S. I have gone through the archives. It seems that 0.5 is always referred as a low value. Not sure why it is so.

try 0.1

Hi Fadhil,

Thanks for the advice. May I know the reasoning in choosing 0.1 or perhaps thre is a calculation that we can use?

Best regards, Woo

try 0.1

courant number is ratio of a time step to a cell residence time..so choose the small ratio.

try 0.1

Hello Woo,

the Courant-Number limit < 1 must be adhered to for explicit time discretitation schemes, especially for Vof-applications or certain high Mach-number flows with shocks where one should use density-based coupled solvers. For single-phase flows or incompressible fluid dynamic problems I met no stability problems using a Courant-number of 20 with the pressure-based coupled solver, provided that you have a good quality grid.

cheers

Max

Hi Max,

Thank you for the advice. No wonder my model failed to converged at the default value of 500. Will try the lower number and see what happens.

cheers, Woo