Convergence in multiphase flow !! HELP !!!
 

Hi, i'm making gas-liquid flow simulations. I began with time step equal to 1e-06 s, otherwise convergence is impossible. it began then to converge, and i can fix time =1e-04s, but after a few time step, convergence is more and more difficult to reach and I have to lower the time step size. Can somebody explain me why ?????

Thanx

Re: Convergence in multiphase flow !! HELP !!!
 

Try increasing the time step by smaller increments!

Re: Convergence in multiphase flow !! HELP !!!
 

yes I did that, but when I get from 1e-06 to 1e-05, it takes 10 to 5 iteration per time step to converge. So I get to 1e-04, then it convergences. And after a few time steps, convergence stops. And time step size wants to be lowered. Thanx though !!!

Re: Convergence in multiphase flow !! HELP !!!
 

try smaller underrelaxation parameters.

newbie

Re: Convergence in multiphase flow !! HELP !!!
 

Hi you can use adaptive time stepping method in place of fixed.