Freeze Flow for Transient Heat Up Simulation

CellZone · August 6, 2018, 08:32

Hello,

I am trying to do a simulation of a cold room, which sees an blower with hot air.

If I switch on the blower and wait for 30min, the room is more or less in a stationary condition.

When I am trying do simulate this transient process, I am wondering, if I can use a fleeze flow condition after a couple of iterations. Yes, due to my blower I have many turbulence and vortexes in my room, but I assume, that the flow field can be assumed to be converged after a couple of seconds (60s) . After this, I would switch on "freeze flow" option.

Do you think this can work? I am not quite sure if I have a highly turbulent flow and I switch on freeze flow to reduce computing time?

Thank you for any hints guys!

FMDenaro · August 6, 2018, 10:39

Quote:

Originally Posted by CellZone

Hello,

I am trying to do a simulation of a cold room, which sees an blower with hot air.

If I switch on the blower and wait for 30min, the room is more or less in a stationary condition.

When I am trying do simulate this transient process, I am wondering, if I can use a fleeze flow condition after a couple of iterations. Yes, due to my blower I have many turbulence and vortexes in my room, but I assume, that the flow field can be assumed to be converged after a couple of seconds (60s) . After this, I would switch on "freeze flow" option.

Do you think this can work? I am not quite sure if I have a highly turbulent flow and I switch on freeze flow to reduce computing time?

Thank you for any hints guys!

No, I don't think that is correct, the fluid is air and Pr=O(1), the bouyancy is relevant and the flow is turbulent.

LuckyTran · August 7, 2018, 14:10

If that is the justification I would verify that the flow is stationary, which requires doing the transient simulation with flow on.

But if you are only looking for a crude answer then it would certainly be helpful to freeze the flow. It depends why you are doing CFD and what you hope to get out of it.

August 6, 2018, 08:32	Freeze Flow for Transient Heat Up Simulation	#1
CellZone Member Join Date: Apr 2016 Posts: 91 Rep Power: 10	Hello, I am trying to do a simulation of a cold room, which sees an blower with hot air. If I switch on the blower and wait for 30min, the room is more or less in a stationary condition. When I am trying do simulate this transient process, I am wondering, if I can use a fleeze flow condition after a couple of iterations. Yes, due to my blower I have many turbulence and vortexes in my room, but I assume, that the flow field can be assumed to be converged after a couple of seconds (60s) . After this, I would switch on "freeze flow" option. Do you think this can work? I am not quite sure if I have a highly turbulent flow and I switch on freeze flow to reduce computing time? Thank you for any hints guys!

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August 7, 2018, 14:10		#3
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,762 Rep Power: 66	If that is the justification I would verify that the flow is stationary, which requires doing the transient simulation with flow on. But if you are only looking for a crude answer then it would certainly be helpful to freeze the flow. It depends why you are doing CFD and what you hope to get out of it.