What is the term "explicit force" between fluid and particles?

Submitted by keepfit on Sun, 09/29/2013 - 03:21

Hi Chris,

I am a bit curious about the term "explicit force" (i.e. expParticleForces in paraview).

When using Model A, the governing equation is referred to Set II according to the paper :

Z. Y, Zhou, et. al (2010), Discrete particle simulation of particle-fluid flow...

As the dominant particle-fluid interaction forces are the drag/lift, pressure gradient and viscous forces, which are presented in the momentum eqn. I wonder if the expParticleForces = f'' = sum of virtual mass force, Basset force and Staff force, etc? and the force f'' is ignored in the cfdem implementation?

Thanks in advance.

David

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cgoniva's picture

cgoniva | Thu, 10/24/2013 - 15:06

Hi David,

there is the possibility to treat interaction terms fully explicit. This has to be indicated in the force's sub-dict. However, the standard solvers use only implicit interaction terms (lumped to Ksl) so I recommend you not to use the treatExplicit option with them.

Cheers,
Chris

keepfit | Fri, 10/25/2013 - 02:41

Hi Chris,

thanks for the explanation. If we consider the forces such as virtual mass force, Basset force etc, does it mean these forces are not added into N-S equation, instead directly passed onto DEM particles?

best,
David