UDF for DPM velocity, relative or real one?

Zeallt · January 26, 2011, 16:11

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, 10:48

Quote:

Originally Posted by Zeallt

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.

January 26, 2011, 16:11	UDF for DPM velocity, relative or real one?	#1
Zeallt New Member Litao Join Date: Jan 2011 Posts: 12 Rep Power: 15	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!!

March 4, 2015, 18:41		#4
virrast New Member Rastko Jovanovic Join Date: Aug 2011 Posts: 7 Rep Power: 15	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. souza.emer likes this.

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February 27, 2015, 15:40		#3
HyperNova Senior Member B_Kia Join Date: May 2014 Location: Ir Posts: 123 Rep Power: 12	it will get the velocity of the particle , not relative velocity!