CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM

direct map vs cyclic

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 13, 2010, 16:39
Default direct map vs cyclic
  #1
Senior Member
 
Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,267
Blog Entries: 1
Rep Power: 25
nimasam is on a distinguished road
im going to modeling a two phase-flow which is heated along pipe, my boundary is cyclic in U and alpha but not in p and T so im going to use following boundary

.............wall..................
inlet outlet
.............axis..................

i would like to direct map of outlet into inlet for alpha and U,

alpha:


inlet
{
type directMapped;
value uniform 0;
setAverage false;
average 0;

}

outlet
{
type zeroGradient;
}

U:

inlet
{
type directMapped;
value uniform (0 0 1);
setAverage true;
average (0 0 1);
}

outlet
{
type zeroGradient;
}
p:
inlet
{
type zeroGradient;
}

outlet
{
type fixedValue;
value uniform 0;
}
T:

inlet
{
type fixedValue;
value uniform 0 ;
}

outlet
{
type zeroGradient;

}

are my boundaries corrects ?
whats the meaning of value,setAverage, and average?
what should be those values for direct map of outlet value into inlet value i want something exactly like cyclic boundary condition for U and alpha?


P.S: i used changeDictionary Dict like below

dictionaryReplacement
{
boundary
{
inlet
{
type directMappedPatch;
offset ( 0 0 4e-5 );
samplePatch outlet;
}
}
}
nimasam is offline   Reply With Quote

Old   December 14, 2010, 05:52
Default
  #2
Senior Member
 
Stefan Herbert
Join Date: Dec 2009
Location: Darmstadt, Germany
Posts: 129
Rep Power: 17
herbert is on a distinguished road
Quote:
Originally Posted by nimasam View Post
are my boundaries corrects ?
I think so.
Quote:
Originally Posted by nimasam View Post
whats the meaning of value,setAverage, and average?
what should be those values for direct map of outlet value into inlet value i want something exactly like cyclic boundary condition for U and alpha?
The value entry is as often ignored by any solver but holds just the actual value of the faces.
If you want to fix the mass flow through your domain for example you can use the average option. If "setAverage" is set to "true" (as you did for U) the values are mapped from the outlet but are scaled in a way to reach the specified "average"-value. Else this entry is ignored, too. So if you don't want to fix your average velocity to (0 0 1) you should turn off the setAverage-option.

Kind regards,
Stefan
herbert is offline   Reply With Quote

Old   February 15, 2017, 12:58
Default
  #3
New Member
 
Michela
Join Date: Mar 2015
Location: Italy
Posts: 7
Rep Power: 11
bargiola is on a distinguished road
Dear Nima

I've got problem similar to yours: I'm trying to perform a LES simulation in a channel and I would like to reproduce cyclic boundary condition only for U, but not for a scalar release from the bottom of the channel.
Have you managed to use directMappedPatch in the correct way?

Can you help me please?

Thanks in advance
Michela
bargiola is offline   Reply With Quote

Reply

Tags
cyclic, directmapped


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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
setup problems - LES pipe flow with cyclic BC (1) and direct mapped inlet (2) florian_krause OpenFOAM 22 June 13, 2013 22:25
Cyclic bc. and overlapGgi Pekka OpenFOAM 12 February 15, 2012 08:10
[Commercial meshers] Handling cyclic BC from gambit to openfoam for a cascade airfoil problem - OF 1.6 maverick OpenFOAM Meshing & Mesh Conversion 2 June 18, 2011 05:36
Pressure instability with rhoSimpleFoam daniel_mills OpenFOAM Running, Solving & CFD 44 February 17, 2011 18:08
fluent add additional zones for the mesh file SSL FLUENT 2 January 26, 2008 12:55


All times are GMT -4. The time now is 21:43.