mass source difficulty

rmawimbe · March 8, 2011, 06:38

Hi, i am trying to model an initial air environment with no inflow from any boundary. i have created a solid stl as a mass source with a positive value and another as a sink with a marginally smaller value,
i have run the simulation and cannot get movement, i have read every detail that i can find, but it eludes me somewhat.

MuxaB · March 12, 2011, 18:34

Hi Robert,

What FLOW-3D version are you working with?

Assuming you are modeling air as compressible fluid, you need to use a two-fluid model with compressible gas (NMAT=2, ICMPRS=1), initialize fluid #2 (gas) in the domain (default). set its initial pressure and temperature (PRESI and TEMPI)

Activate mass source model for the second fluid, IQSR=2, and define to solid components with the mass flow rate defined. The temperature and density at the source must also be deifne, RHOQSR and TQSR.

If you are modeling air as incompressible fluid, then it is a bit simpler. You need to use the one -fluid model with no free surface (NMAT=1, ITB=0), initialize fluid #1 in the domain (default).

Activate mass source model for the second fluid, IQSR=1, and define to solid components with the mass flow rate defined.

rmawimbe · March 14, 2011, 14:58

Thank you Michael for the reply,
I think it is 9.3v, I am modeling as incompressible for now, but assuming
(second fluid, IQSR=1,) was a typo i thought that i had done exactly that.
I have a slot later in the week, I'll double check. thanks again Robert

MuxaB · March 14, 2011, 15:33

yes, of course, i meant activate mass source for the first fluid with IQSR=1, sorry.

How come you are running such an old version? Does it have a customization?

March 14, 2011, 14:58	reply	#3
rmawimbe New Member robert Join Date: Mar 2011 Posts: 3 Rep Power: 15	Thank you Michael for the reply, I think it is 9.3v, I am modeling as incompressible for now, but assuming (second fluid, IQSR=1,) was a typo i thought that i had done exactly that. I have a slot later in the week, I'll double check. thanks again Robert

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March 8, 2011, 06:38	mass source difficulty	#1
rmawimbe New Member robert Join Date: Mar 2011 Posts: 3 Rep Power: 15	Hi, i am trying to model an initial air environment with no inflow from any boundary. i have created a solid stl as a mass source with a positive value and another as a sink with a marginally smaller value, i have run the simulation and cannot get movement, i have read every detail that i can find, but it eludes me somewhat.

March 12, 2011, 18:34		#2
MuxaB Senior Member michael barkhudarov Join Date: Mar 2009 Location: Sante Fe, New Mexico, USA Posts: 337 Rep Power: 18	Hi Robert, What FLOW-3D version are you working with? Assuming you are modeling air as compressible fluid, you need to use a two-fluid model with compressible gas (NMAT=2, ICMPRS=1), initialize fluid #2 (gas) in the domain (default). set its initial pressure and temperature (PRESI and TEMPI) Activate mass source model for the second fluid, IQSR=2, and define to solid components with the mass flow rate defined. The temperature and density at the source must also be deifne, RHOQSR and TQSR. If you are modeling air as incompressible fluid, then it is a bit simpler. You need to use the one -fluid model with no free surface (NMAT=1, ITB=0), initialize fluid #1 in the domain (default). Activate mass source model for the second fluid, IQSR=1, and define to solid components with the mass flow rate defined.

March 14, 2011, 15:33		#4
MuxaB Senior Member michael barkhudarov Join Date: Mar 2009 Location: Sante Fe, New Mexico, USA Posts: 337 Rep Power: 18	yes, of course, i meant activate mass source for the first fluid with IQSR=1, sorry. How come you are running such an old version? Does it have a customization?