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

flying · June 3, 2009, 10:23

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, 10:57

Hi,

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

Regards,

Leonardo

ngj · June 3, 2009, 11:11

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, 11:25

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

flying · June 4, 2009, 12:08

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, 15:59

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, 08:50

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, 09:26

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

June 3, 2009, 10:23	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!

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Changing deltaT of current time step	olwi	OpenFOAM Running, Solving & CFD	1	April 30, 2009 04:55
DPM UDF particle position using the macro P_POS(p)[i]	dm2747	FLUENT	0	April 17, 2009 01:29
Differences between serial and parallel runs	carsten	OpenFOAM Bugs	11	September 12, 2008 11:16
Modeling in micron scale using icoFoam	m9819348	OpenFOAM Running, Solving & CFD	7	October 27, 2007 00:36
Could anybody help me see this error and give help	liugx212	OpenFOAM Running, Solving & CFD	3	January 4, 2006 18:07

June 3, 2009, 10:57		#2
leonardo.morita Member Leonardo Giampani Morita Join Date: Apr 2009 Location: Paris, France Posts: 58 Rep Power: 16	Hi, I've not used it yet, but it seems that timeVaryingMappedFixedValue can be useful for you. Regards, Leonardo

June 3, 2009, 11:11		#3
ngj Senior Member Niels Gjoel Jacobsen Join Date: Mar 2009 Location: Copenhagen, Denmark Posts: 1,900 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, 11:25		#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, 12:08		#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, 15:59		#6
leonardo.morita Member Leonardo Giampani Morita Join Date: Apr 2009 Location: Paris, France Posts: 58 Rep Power: 16	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, 08:50		#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, 09:26		#8
leonardo.morita Member Leonardo Giampani Morita Join Date: Apr 2009 Location: Paris, France Posts: 58 Rep Power: 16	Here: OpenFOAM-1.5\src\finiteVolume\fields\fvPatchFields\derived