CFD Online URL
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

Robin B.C=Mixed B.C ?

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   October 23, 2009, 14:41
Question Robin B.C=Mixed B.C ?
  #1
New Member
 
Kaveh Sookhak Lari
Join Date: Oct 2009
Location: London
Posts: 2
Rep Power: 0
ksookhak is on a distinguished road
Send a message via Yahoo to ksookhak
Hi

Fro the Robin B.C:

dC/dy = a * C

where a is constant, C is scalar concentration and y is direction normal to the wall, How can I use the Mixed B.C? What will be the following terms?

refValue, refGradient, valueFraction and value?

Thanks in advance!
ksookhak is offline   Reply With Quote

Old   January 5, 2011, 09:37
Default Robin BC
  #2
New Member
 
sprenger
Join Date: Aug 2010
Posts: 2
Rep Power: 0
spl1504 is on a distinguished road
Hi all,

some already posted the same question as I have here, but I could not find any answer that helped me.

I need to implement a Robin boundary condition of the form

c=a*dc/dx

with "a" being a constant, "x" the axis and "c" my volScalarField which is calculated by just one PDE (c(t,x,y,z)).
Can anyone give me a hint? I am not too familiar with programming in C++, so I have difficulties to understand the code of the OpenFOAM boundary conditions....

Maybe the answer is obvious for some of you, but unfortunately not for me, so I would really appreciate a help ...

Thanx
spl1504 is offline   Reply With Quote

Old   January 10, 2011, 05:55
Default
  #3
Member
 
Usit McCarra
Join Date: Oct 2010
Posts: 51
Blog Entries: 2
Rep Power: 6
McCarra is on a distinguished road
All types of boundary conditions for a volScalarField are:

advective
buoyantPressure
calculated
cellMotion
cyclic
directMapped
directionMixed
empty
fan
fixedFluxPressure
fixedGradient
fixedInternalValue
fixedPressureCompressibleDensity
fixedValue
freestream
freestreamPressure
inletOutlet
inletOutletTotalTemperature
mixed
oscillatingFixedValue
outletInlet
outletMappedUniformInlet
partialSlip
processor
rotatingTotalPressure
sliced
slip
surfaceSlipDisplacement
symmetryPlane
syringePressure
timeVaryingMappedFixedValue
timeVaryingMappedTotalPressure
timeVaryingTotalPressure
timeVaryingUniformFixedValue
timeVaryingUniformInletOutlet
totalPressure
totalTemperature
turbulentInlet
turbulentIntensityKineticEnergyInlet
uniformDensityHydrostaticPressure
uniformFixedValue
waveTransmissive
wedge
zeroGradient

In the thread "movingCone with time-dependent displacement" are also all the types por pointScalarField and volVectorField.

Maybe one of these types could help you!
McCarra is offline   Reply With Quote

Old   January 11, 2011, 10:50
Default
  #4
Senior Member
 
Ben K
Join Date: Feb 2010
Location: Ottawa, Canada
Posts: 140
Rep Power: 9
benk is on a distinguished road
I think the solution to your problem is in this post:
Mixed boundary condition

which I basically stole from this post:
Mixed BC - heat transfer - laplacianFoam
benk is offline   Reply With Quote

Old   January 12, 2011, 05:11
Default
  #5
New Member
 
sprenger
Join Date: Aug 2010
Posts: 2
Rep Power: 0
spl1504 is on a distinguished road
So, unfortunately there seems to be no way to get around groovyBC when I am looking for a very general BC?!

I had a closer look at the other BCs but did not succeed in actually understand them, they seem very specific to me.

I downloaded groovyBC and followed the instructions on http://openfoamwiki.net/index.php/Contrib_groovyBC
but when I run the demo cases and use paraview for the visualisation, I always get a problem by seeing the velocity U, paraview shuts down directly. I tried the two versions of the libs hint, given on the website, but this did not change the problem. Does anyone have an idea what could be wrong?

(I use OpenFOAM-1.6.x).

Thank you very much..
spl1504 is offline   Reply With Quote

Old   January 12, 2011, 11:33
Default
  #6
Senior Member
 
Ben K
Join Date: Feb 2010
Location: Ottawa, Canada
Posts: 140
Rep Power: 9
benk is on a distinguished road
I'm not sure about your paraview problems, maybe try posting/searching this thread: http://www.cfd-online.com/Forums/ope...burb-mesh.html

It seems as if groovyBC is just an interface for the mixed boundary condition which shows up in the list posted by McCarra above. So if you're good at C++ and don't want to use groovyBC, then you can try compiling your own boundary condition based on mixed.
benk is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Robin B.C. Yu FLUENT 3 May 27, 2012 05:19
Confusion between 'non-slip' and 'slip' B.C jinwon park Main CFD Forum 7 March 6, 2008 05:56
Urgent! Help on UDF to set B.C. of 3rd type Ray Hong FLUENT 0 December 28, 2005 20:35
How to set B.C. of the 2nd or 3rd type in UDS? Ray Hong FLUENT 0 December 28, 2005 07:03
Robin B.C. yu Phoenics 0 July 16, 2002 07:39


All times are GMT -4. The time now is 08:15.