How to set up the velocity in the let boudary changing with time.

flying · June 3, 2009, 11:23

Hey Foamers:

I wish all of you have a nice day.
I need to simulate a case that the velocity in the inlet changes with the time.
How do I set up it ?
Is there existed solver or text that could be referenced by me?

Thanks and best wishes!

leonardo.morita · June 3, 2009, 11:57

Hi,

I've not used it yet, but it seems that timeVaryingMappedFixedValue can be useful for you.

Regards,

Leonardo

ngj · June 3, 2009, 12:11

And if the time variation can be specified by a mathematical expression you would benefit from groovyBC (just search the forum).

Best regards,

Niels

flying · June 3, 2009, 12:25

Thanks a lot to eonardo and Niels. I will try it.

flying · June 4, 2009, 13:08

Hey Leonardo:

I have read the thread, but it is very sad that I know few thing about "timeVaryingMappedFixedValue". Is it a utility?
How do I use it? And how could I generate the value for different time step?

Thanks and Best wishes!

leonardo.morita · June 4, 2009, 16:59

Hello,

Well, I know it's not extensively documented, but you can search for more info here in the forum. Try the keywords: transient boundary conditions, timeVarying, nonuniform boundary conditions etc.

About your questions:

"Is it a utility?"
- it's a kind of boundary condition you can use with U, p etc (like fixedValue, zeroGradient...)

"How do I use it?"
- you can take a look into the simpleFoam/pitzDailyExptInlet tutorial for syntax and more

"And how could I generate the value for different time step?"
- as I don't know anything about your case and as I've never used it, it's a bit difficult to answer this one

Regards,

Leonardo

flying · June 5, 2009, 09:50

Thanks for your answer. I would like to know where I could see the source code for this boundary condition. I guess from the source code, I could get more information.

Best wishes!

leonardo.morita · June 5, 2009, 10:26

Here: OpenFOAM-1.5\src\finiteVolume\fields\fvPatchFields\derived

June 3, 2009, 11:23	How to set up the velocity in the let boudary changing with time.	#1
flying Senior Member xinguang cui Join Date: Mar 2009 Posts: 116 Rep Power: 17	Hey Foamers: I wish all of you have a nice day. I need to simulate a case that the velocity in the inlet changes with the time. How do I set up it ? Is there existed solver or text that could be referenced by me? Thanks and best wishes!

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June 3, 2009, 11:57		#2
leonardo.morita Member Leonardo Giampani Morita Join Date: Apr 2009 Location: Paris, France Posts: 58 Rep Power: 17	Hi, I've not used it yet, but it seems that timeVaryingMappedFixedValue can be useful for you. Regards, Leonardo

June 3, 2009, 12:11		#3
ngj Senior Member Niels Gjoel Jacobsen Join Date: Mar 2009 Location: Copenhagen, Denmark Posts: 1,902 Rep Power: 37	And if the time variation can be specified by a mathematical expression you would benefit from groovyBC (just search the forum). Best regards, Niels

June 3, 2009, 12:25		#4
flying Senior Member xinguang cui Join Date: Mar 2009 Posts: 116 Rep Power: 17	Thanks a lot to eonardo and Niels. I will try it.

June 4, 2009, 13:08		#5
flying Senior Member xinguang cui Join Date: Mar 2009 Posts: 116 Rep Power: 17	Hey Leonardo: I have read the thread, but it is very sad that I know few thing about "timeVaryingMappedFixedValue". Is it a utility? How do I use it? And how could I generate the value for different time step? Thanks and Best wishes!

June 4, 2009, 16:59		#6
leonardo.morita Member Leonardo Giampani Morita Join Date: Apr 2009 Location: Paris, France Posts: 58 Rep Power: 17	Hello, Well, I know it's not extensively documented, but you can search for more info here in the forum. Try the keywords: transient boundary conditions, timeVarying, nonuniform boundary conditions etc. About your questions: "Is it a utility?" - it's a kind of boundary condition you can use with U, p etc (like fixedValue, zeroGradient...) "How do I use it?" - you can take a look into the simpleFoam/pitzDailyExptInlet tutorial for syntax and more "And how could I generate the value for different time step?" - as I don't know anything about your case and as I've never used it, it's a bit difficult to answer this one Regards, Leonardo

June 5, 2009, 09:50		#7
flying Senior Member xinguang cui Join Date: Mar 2009 Posts: 116 Rep Power: 17	Thanks for your answer. I would like to know where I could see the source code for this boundary condition. I guess from the source code, I could get more information. Best wishes!

June 5, 2009, 10:26		#8
leonardo.morita Member Leonardo Giampani Morita Join Date: Apr 2009 Location: Paris, France Posts: 58 Rep Power: 17	Here: OpenFOAM-1.5\src\finiteVolume\fields\fvPatchFields\derived