Multi Fluid domain problem in Fluent

steeph · January 6, 2022, 05:36

Hello,

I am trying to perform a CFD simulation with two separate fluid domain and a solid domain. The two fluid domain do not mix and are completely separate.

Can Fluent handle such problems with different fluid domains? I am facing a number of errors and could not proceed with the solution. I would greatly appreciate any input in this matter.

Kindly,
Stephen

LuckyTran · January 6, 2022, 20:29

Two different domains is by definition two different domains. They belong to different universes. What exactly are you trying to simulate? Give relevant details rather than an indefinite number of unexplained errors.

Fluent can do a lot of things. But without knowing anything, we cannot say anything meaningful. That being said, Fluent (and several other software) are very robust solvers and can handle just about anything you can possibly think of as long as it is within the realm of continuum mechanics (i.e. fluids). Fluent does not solve molecular dynamics or dna and protein folding; but as long as it is a Fluid, Fluent likely can simulate it. If Fluent can't, probably nothing else can either.

steeph · January 7, 2022, 03:30

Hello Lucky tran,

Sorry for the vague details. By two fluid domains I meant there are two fluid zones that does not connect or mix at any point. The two fluid volumes are above and below a solid bar whuch is the source of heat. So, there are two inlets and two outlets. I read in some place that Fluent is well optimised to handle problems with multiple inlets and outlets and that why I had doubt if Fluent can solve problems with multiple fluid zones.

As soon as I press initialise, Fluent crashes and closes. It generates several error files
Node 0.... Abnormal Exit
Node 1.... Abnormal Exit
and so on till Node 999999... Abnormal Exit

AlexanderZ · January 7, 2022, 03:55

you have problems with mesh or settings.
start with fluid in one region and solid everywhere else.
later switch solid to fluid in the second zone

steeph · January 7, 2022, 04:37

Hello Alexander,

Does these error codes mean that there is problem with the mesh or settings? Can ypu explain whatthese errors mean?

The simulations works fine if I supress one fluid zoneand preserve all other zones.

LuckyTran · January 7, 2022, 04:57

These are parallel errors that don't mean anything other than something crashed.

Are you using the automatic initialization? Use the standard initialization. If that doesn't work then you have something seriously wrong with your setup.

Also, I've done these multi region simulations before. And so have many others before you. Fluent can do it.

steeph · January 7, 2022, 05:18

Thank you. I will try the standard initialisation .

I am using default K-Omega SST model. Do I have turn on any options or use tools if I have more more than one fluid regions. I am kind of new in using Fluent and Ill be grateful for any input in this regard.

LuckyTran · January 7, 2022, 09:24

To simulate multiple zones, you simply need to provide the mesh of the zones, and then declare them as separate zones. It is no different than simulating a case with one fluid zone and one solid zone, except that you have more of each. There might be another million options you need to eventually turn on related to how to actually simulate the thingy you want to simulate, but it is not simply b/c you have multiple zones. You can't initialize your case because you can't initialize your case and it is not related to the number of zones you have.

January 6, 2022, 05:36	Multi Fluid domain problem in Fluent	#1
steeph New Member Paul Stephen Join Date: Nov 2021 Posts: 4 Rep Power: 4	Hello, I am trying to perform a CFD simulation with two separate fluid domain and a solid domain. The two fluid domain do not mix and are completely separate. Can Fluent handle such problems with different fluid domains? I am facing a number of errors and could not proceed with the solution. I would greatly appreciate any input in this matter. Kindly, Stephen

January 7, 2022, 03:55		#4
AlexanderZ Senior Member Alexander Join Date: Apr 2013 Posts: 2,363 Rep Power: 34	you have problems with mesh or settings. start with fluid in one region and solid everywhere else. later switch solid to fluid in the second zone __________________ best regards ****************************** press LIKE if this message was helpful

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January 6, 2022, 20:29		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 66	Two different domains is by definition two different domains. They belong to different universes. What exactly are you trying to simulate? Give relevant details rather than an indefinite number of unexplained errors. Fluent can do a lot of things. But without knowing anything, we cannot say anything meaningful. That being said, Fluent (and several other software) are very robust solvers and can handle just about anything you can possibly think of as long as it is within the realm of continuum mechanics (i.e. fluids). Fluent does not solve molecular dynamics or dna and protein folding; but as long as it is a Fluid, Fluent likely can simulate it. If Fluent can't, probably nothing else can either.

January 7, 2022, 03:30		#3
steeph New Member Paul Stephen Join Date: Nov 2021 Posts: 4 Rep Power: 4	Hello Lucky tran, Sorry for the vague details. By two fluid domains I meant there are two fluid zones that does not connect or mix at any point. The two fluid volumes are above and below a solid bar whuch is the source of heat. So, there are two inlets and two outlets. I read in some place that Fluent is well optimised to handle problems with multiple inlets and outlets and that why I had doubt if Fluent can solve problems with multiple fluid zones. As soon as I press initialise, Fluent crashes and closes. It generates several error files Node 0.... Abnormal Exit Node 1.... Abnormal Exit and so on till Node 999999... Abnormal Exit

January 7, 2022, 04:37		#5
steeph New Member Paul Stephen Join Date: Nov 2021 Posts: 4 Rep Power: 4	Hello Alexander, Does these error codes mean that there is problem with the mesh or settings? Can ypu explain whatthese errors mean? The simulations works fine if I supress one fluid zoneand preserve all other zones.

January 7, 2022, 04:57		#6
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 66	These are parallel errors that don't mean anything other than something crashed. Are you using the automatic initialization? Use the standard initialization. If that doesn't work then you have something seriously wrong with your setup. Also, I've done these multi region simulations before. And so have many others before you. Fluent can do it.

January 7, 2022, 05:18		#7
steeph New Member Paul Stephen Join Date: Nov 2021 Posts: 4 Rep Power: 4	Thank you. I will try the standard initialisation . I am using default K-Omega SST model. Do I have turn on any options or use tools if I have more more than one fluid regions. I am kind of new in using Fluent and Ill be grateful for any input in this regard.

January 7, 2022, 09:24		#8
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 66	To simulate multiple zones, you simply need to provide the mesh of the zones, and then declare them as separate zones. It is no different than simulating a case with one fluid zone and one solid zone, except that you have more of each. There might be another million options you need to eventually turn on related to how to actually simulate the thingy you want to simulate, but it is not simply b/c you have multiple zones. You can't initialize your case because you can't initialize your case and it is not related to the number of zones you have.