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-   -   fn(ijk) and f(ijk) and vf(ijk) (http://www.cfd-online.com/Forums/flow-3d/69213-fn-ijk-f-ijk-vf-ijk.html)

shokry October 15, 2009 10:42

fn(ijk) and f(ijk) and vf(ijk)
 
I want to know the difference between fn(ijk) and f(ijk) and vf(ijk)
the difference as indicated in flow 3d is

vf(ijk) open volume fraction in cell (related to the solid and fluid)
f(ijk) fluid fraction in cell at beginning of cycle (related to void)
fn(ijk) fluid fraction in cell at beginning of cycle
but I want to know more detailed spicially for fn(ijk)

MuxaB October 19, 2009 23:59

hi shokry,

it is quite simple and you got most of it already. fn and f are the volume fractions of fluid in the cell's open volume, i.e., the total fluid volume in a cell is f*vf*dx*dy*dz (or fn*vf*dx*dy*dz).

f=fn at the beginning of each time step. During the time step f accumulates incremental changes from advection, phase change, sources, moving boundaries and so on. at the end of the time step f constitues the new fluid configuration, fn - the old. and so on. makes sense?

michael

shokry October 20, 2009 05:00

thanks michael


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