Unit vector from cell centroid to the boundary face

Achini · October 11, 2020, 04:00

Hello!

I am planning to model particle attractions with the channel wall.
To get the force exerted by the channel wall to the particle, I'm planning to use DPM_BODYFORCE macro.

In order to get the resultant force, I need to get the unit vector from a cell to the boundary. how can i find it?

also how can i create a loop to loop over the cells in the boundary?

I'd be greatful if anyone could help me with this.

Thank you!

AlexanderZ · October 12, 2020, 06:39

the macro is

Code:

DEFINE_DPM_BODY_FORCE

the adjacent cell’s variables values could be found using F_C0(f,t),THREAD_T0(t) and F_C1(f,t),THREAD_T1(t) macros (c1 t1 in case the face is interior)

not sure what is unit vector

i recommend you to read Ansys Fluent Customization manual, you may find some examples there

Achini · October 12, 2020, 10:26

Hello AlexanderZ,

Thank you for your reply.

Do you know of a method to distinguish between particles injected via two separation injections (Injection 0 & Injection 1). Injected particles from both injections are identicle execpt for their surface properties.

once a particle is located, I want to identify whethher it is from injection 0 or injection 1.

I'd be greatful if you could help me with this.

Thank you!

October 11, 2020, 04:00	Unit vector from cell centroid to the boundary face	#1
Achini Member L.A.Isanka Join Date: Jul 2020 Posts: 55 Rep Power: 5	Hello! I am planning to model particle attractions with the channel wall. To get the force exerted by the channel wall to the particle, I'm planning to use DPM_BODYFORCE macro. In order to get the resultant force, I need to get the unit vector from a cell to the boundary. how can i find it? also how can i create a loop to loop over the cells in the boundary? I'd be greatful if anyone could help me with this. Thank you! Last edited by Achini; October 11, 2020 at 04:00. Reason: fluent, udf, vector, loop, position vector

October 12, 2020, 06:39		#2
AlexanderZ Senior Member Alexander Join Date: Apr 2013 Posts: 2,363 Rep Power: 34	the macro is Code: DEFINE_DPM_BODY_FORCE the adjacent cell’s variables values could be found using F_C0(f,t),THREAD_T0(t) and F_C1(f,t),THREAD_T1(t) macros (c1 t1 in case the face is interior) not sure what is unit vector i recommend you to read Ansys Fluent Customization manual, you may find some examples there Achini likes this. __________________ best regards ****************************** press LIKE if this message was helpful

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October 12, 2020, 10:26		#3
Achini Member L.A.Isanka Join Date: Jul 2020 Posts: 55 Rep Power: 5	Hello AlexanderZ, Thank you for your reply. Do you know of a method to distinguish between particles injected via two separation injections (Injection 0 & Injection 1). Injected particles from both injections are identicle execpt for their surface properties. once a particle is located, I want to identify whethher it is from injection 0 or injection 1. I'd be greatful if you could help me with this. Thank you!