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

Boundary conditions for external flows

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

Reply
 
LinkBack Thread Tools Display Modes
Old   May 18, 2008, 23:33
Default Hi, Im running 3D airfoils
  #1
New Member
 
Ryan Middleton
Join Date: Mar 2009
Posts: 17
Rep Power: 7
ryan_m is on a distinguished road
Hi,

Im running 3D airfoils (NACA 0016 @ 0 degrees) using an incompressible solver (simpleFoam). The results Im getting aren't making much sense: non-symmetrical pressure distribution, the velocity at the inlet seems to be different to what I specified. I think my boundary conditions are at fault. Could someone please have a look at the following boundary conditions to see if there are any errors:

Pressure: fixedValue outlet, zeroGradient elsewhere

Velocity: fixedValue inlet, zeroGradient outlet, movingWallVelocity on boundaries and 0 at the airfoil walls

k, epsilon, nuTilda: fixedValue inlet, zeroGradient elesewhere

Any help will be much appreciated.

Ryan
ryan_m is offline   Reply With Quote

Old   May 19, 2008, 07:41
Default Hi Ryan The movingWallVeloc
  #2
ngj
Senior Member
 
Niels Gjoel Jacobsen
Join Date: Mar 2009
Location: Rotterdam, The Netherlands
Posts: 1,524
Rep Power: 23
ngj will become famous soon enoughngj will become famous soon enough
Hi Ryan

The movingWallVelocity, is that on the side walls parallel to the longitudinal direction of the channel? I would put a symmetry condition on those walls, see e.g. User Guide sec 6.2.1.

The other boundary conditions look reasonable.

- Niels
__________________
Please note that I do not use the Friend-feature, so do not be offended, if I do not accept a request.
ngj is offline   Reply With Quote

Old   May 19, 2008, 08:18
Default Hi Niels, I do have a symme
  #3
New Member
 
Ryan Middleton
Join Date: Mar 2009
Posts: 17
Rep Power: 7
ryan_m is on a distinguished road
Hi Niels,

I do have a symmetry plane in the mesh which I defined as a symmetryPlane (forgot to mention that in original post!). The movingWallVelocity is for the top, bottom and side of my domain. I am currently running the case now, Ill post another comment if my results dont work out.

Thanks for your comments.

Ryan
ryan_m is offline   Reply With Quote

Old   May 19, 2008, 09:49
Default Hi Ryan, movingWallVelocity
  #4
pbo
Member
 
Patrick Bourdin
Join Date: Mar 2009
Posts: 40
Rep Power: 7
pbo is on a distinguished road
Hi Ryan,

movingWallVelocity is for moving/deforming boundaries;
for a static mesh, used fixedValue for the Velocity at the top, bottom and side boundaries if what you want is to prescribe the velocity on these patches.
However, you will be better off using the slip condition on those.

Patrick
pbo 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
Fan Boundary conditions with external analysis Rob FloEFD, FloWorks & FloTHERM 1 February 10, 2009 00:04
Inlet turbulent boundary condition: external flows ROOZBEH FLUENT 2 February 8, 2009 07:02
Inlet turbulent boundary condition, external flows ROOZBEH Main CFD Forum 1 February 6, 2009 12:37
Boundary Conditions for External Flow raytracer OpenFOAM Running, Solving & CFD 4 July 14, 2008 12:18
boundary conditions for external automotive aero Andrew Berner FLUENT 4 November 2, 2006 11:17


All times are GMT -4. The time now is 04:18.