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-   -   Some nondimensinal Parameters (http://www.cfd-online.com/Forums/fluent/30714-some-nondimensinal-parameters.html)

American Larki December 21, 2002 19:39

Some nondimensinal Parameters
 
Happy X-mass everyone in the forum !!

I have an engineering degree from a very best Uni. I thought I was smart, but this FLUENT is making me crazy !! Could you please help me out?

1) Whats the the easiest way to calculate the relative velocity of particle (Lagrangian)? 2) How do I calculate the Stoke number in Fluent? Terminal settling (rising) velocity? Acceleration of relative particle velocity? 3) At a certain point and time, how do I calculate (know) which force is dominating on the particle? How do I know easily the forces on that point and time on that particle (gravity, pressure, lift force, virtiual mass force etc)? I want to know the magnitude and direction? 4) How do I calculate the gradient of particle velocity? 5) Saffman Lift force in FLUENT is only for unsteady calculation, am I correct? 6) Particles suspended for indefinite time can't be modeled by FLUENT, am I correct? 7) For steady state particulate flow calculation, there is no particle accummulation in the domain, am I correct? 8) How do I calculate the particle loading in an steady and unsteady case (Lagrangian)? Local loading and total loading? In Lagrangian particle tracking (DPM), particle volume fraction doesn't make any sense right? 9) When should I enable BOTH random walk model and cloud model? Why? 10) How do I hanle swirling of fluid and particles? In the experiment how do they get swirling? In Fluent, unless I set some of swirling component, I won't get any swirling neighter for the fluid nor for the particles, am I correct? 11) Fluent can't handle four-way coupling, am I correct ? 12) If I use VOF, do I have to enable full buoyance effect (model>viscous)? What about if I inject buoyant particles, do I have enable this? What force does it account for? 13) Do you really believe like many others that VOF in Fluent is total crap? How can you validate this model if you don't believe? 14) When I have to define a domain with 10 micron-2 mm size cells, Gambit is NO good. What are the alternatives do I have? Can I generate the mesh in Autocad and then import to Fluent, any guideline? 15)How does the particles affect the primary fluid turbulence and how does the turbulence of primary flow affect the particle motion? Does Fluent calculate particle turbulence for higher Re_p?

I may have many questions, I have just thrown the easiest ones, I think.

Regards,

American larki tuki72@hotmail.com


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