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

How to model a fixedValueFixedGradient boundary condition

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 25, 2011, 16:40
Default How to model a fixedValueFixedGradient boundary condition
  #1
New Member
 
BT
Join Date: Jan 2011
Posts: 16
Rep Power: 6
MasterCooler is on a distinguished road
Dear openFOAM-community,

I am still new in the simulation with openFOAM but really impressed by its potential.

Now I try to solve some simple structural problems like a beam fixed on one end. For this problem a boundary condition is required which combines fixedValue and fixedGradient (or the special case zeroGradient and zeroValue, also known as Cauchy boundary condition). So far I couldn't find a boundary condition neither in the supporting material of openFOAM nor in web discussions and articles which provides the required functionality.

To clarify the situation of understanding:
I have seen the mixed bc which switches between fixedGradient and fixedValue. But as I see there is only a switching and not really a combination applying both in a full strength a the same time.

Maybe there is a need to solve this problem on code level, isn't it? Or is there a bc which I have overlooked all the time?

Background information:
Currently I am mainly a user and I am really less experienced in interpreting code. So be careful with hints assuming a deep knowledge of programming. ;-)

Thanks in advance for any help.

Cheers
MasterCooler
MasterCooler is offline   Reply With Quote

Old   July 26, 2011, 05:00
Default
  #2
Senior Member
 
bigphil's Avatar
 
Philip Cardiff
Join Date: Mar 2009
Location: Dublin,Ireland
Posts: 570
Rep Power: 19
bigphil will become famous soon enoughbigphil will become famous soon enough
Hi,

The directionMixed boundary condition can be used to apply a fixedValue in a particular direction and a fixedGradient in the corresponding tangential direction. It can also be used to mix between both fixedValue and fixedGradient.

Also there is a boundary condition called newDirectionMixed (only in the Extend version I think) which can mix both the normal direction and the tangential direction.

In stress analysis, the directionMixed BC can be used for applying a fixed displacement in a particular direction on a patch, and applying a traction in the tangential direction (eg traction-free).

Hope it helps,
Philip
bigphil is offline   Reply With Quote

Reply

Tags
boundary condition, openfoam, structural analysis

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
Water subcooled boiling Attesz CFX 7 January 5, 2013 04:32
Epsilon boundary condition for walls in LamBremhorst LowRe model maruthamuthu_venkatraman OpenFOAM 0 March 16, 2010 04:27
mass flow in is not equal to mass flow out saii CFX 2 September 18, 2009 08:07
Water vapour condensation in CFX-5.7.1 hdj CFX 1 November 27, 2005 08:15
Convective Heat Transfer - Heat Exchanger Mark CFX 6 November 15, 2004 16:55


All times are GMT -4. The time now is 11:32.