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-   -   UDF for DPM velocity, relative or real one? (http://www.cfd-online.com/Forums/fluent-udf/84344-udf-dpm-velocity-relative-real-one.html)

Zeallt January 26, 2011 16:11

UDF for DPM velocity, relative or real one?
 
Hey, folks,

I just noticed this problem, is the velocity UDF used for DPM module a relative speed to fluid, or it is already the actual speed,

that is, like, P_VEL(p)[i], what will get?


thx!!

nayn June 14, 2012 09:48

Quote:

Originally Posted by Zeallt (Post 292326)
Hey, folks,

I just noticed this problem, is the velocity UDF used for DPM module a relative speed to fluid, or it is already the actual speed,

that is, like, P_VEL(p)[i], what will get?


thx!!


so zeallt, do you solve the problem? because i have the same question now and i find that if the velocity in injection set the same with the boudary condition , the simulation results are not acceptable.

Na

HyperNova February 27, 2015 15:40

it will get the velocity of the particle , not relative velocity!

virrast March 4, 2015 18:41

P_VEL(p)[i] gives particle velocity (not relative velocity) components.
i takes values 0,1,2 corresponding to x-, y-, z- velocity components.
Refer to DEFINE DPM_SPRAY_COLLIDE udf example, there is an expression for relative velocity calculation in it.


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