multiphase granular flows; options for secondary phase
 

Hi,

I am working through a FLUENT tutorial where a impeller mixes a vessel with 1/3 sand and 2/3 water

@ moderator: I do not know if I am allowed to provide the ANSYS Tutorial here, otherwise please delete the link.

When specifying the secondary phase, there are different options to be specified. I really worked through the FLUENT user guide, the FLUENT theory guide and there mentioned papers.

Especially for

- the granular viscosity (kintetic part of the viscosity) --> "symlial-obrian" or "gidaspow"
- the granular bulk viscosity (resistance to diletation) --> "lun-et-al" or constant value

I do not understand the difference.

The according ANSYS user/theory guides just mention the options and related formulas. Also after reading through the related papers (Lun et al. & Symlial et al.) and hardly understanding their theories I can not figure out when/why to use which option for the two above mentioned parameters.

Can someone maybe explain me the differences of the options -- respectively in which to use in which cases -- for both parameters?

Thank you very much in advance.

kind regards
RockOn

Nobody out there who can help me?