[sccience]

Hello,
would you please give me a hint about following issue:
how can I modify lagrangian time steps in openfoam. it seems that lagrangian and eulerian time steps are the same. i mean how can i set the solver time step for example at 0.0001s and lagrangian time step at 0.001s.?

[dscian]

It's unusual to have smaller CFD timestep than particle timestep though. There is maxCo (default 0.3) definition in Lagrangian solvers which creates step fractions in CFD timestep for Lagrangian calculations which means you can have smaller timesteps using this. So I don't think it's possible to skip lagrangian calculations in CFD timestep. Moreover, I don't know what happens if maxCo is bigger than 1.

Other option would be to use some other CFD-DEM coupling where you use OpenFOAM and other DEM software such as LIGGGHTS so that you can define DEM timestep yourself.

[sccience]

Originally Posted by dscian

It's unusual to have smaller CFD timestep than particle timestep though. There is maxCo (default 0.3) definition in Lagrangian solvers which creates step fractions in CFD timestep for Lagrangian calculations which means you can have smaller timesteps using this. So I don't think it's possible to skip lagrangian calculations in CFD timestep. Moreover, I don't know what happens if maxCo is bigger than 1.

Other option would be to use some other CFD-DEM coupling where you use OpenFOAM and other DEM software such as LIGGGHTS so that you can define DEM timestep yourself.

Thank you for your reply. I made a mistake in my first post. I want to make lagrangian time step smaller than eulerian ones. As you know maybe there is not need to couple lagarngian and eulerian solvers in every time steps. So this can be vey cost effective.