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

Farfield BC: vortex correction for lifting bodies

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 30, 2005, 12:17
Default Farfield BC: vortex correction for lifting bodies
  #1
zonexo
Guest
 
Posts: n/a
Hi,

i'm reading Blazek's CFD book and he said that for the farfield BC of lifting bodies, some corrections have to be made, namely in 2D,

u(inf)(new) = u(inf) + (tau*sqrt(1-M(inf)^2)/2*pi*d)*sin(theta)/(1-M(inf)^2* (sin(theta-alpha))^2)

v(inf)(new) = v(inf) + (tau*sqrt(1-M(inf)^2)/2*pi*d)*cos(theta)/(1-M(inf)^2* (sin(theta-alpha))^2)

tau is circulation, (d,theta) are polar coordinates of farfield, M(inf) is freestream mach no.

I would like to check if I can apply this to incompressible NS eqns. I'm using the fractional-step btw. Moreover, is this helpful in incompressible flow? It's stated that the farfield radius can be reduced by an order of magnitude when used.

please comment. thanks!

  Reply With Quote

Old   August 30, 2005, 23:52
Default Re: Farfield BC: vortex correction for lifting bod
  #2
Praveen. C
Guest
 
Posts: n/a
This correction can be applied for lifting flows. Hence it is most appropriate for subsonic flows but might also help for transonic flows. For imcompressible flow, I think it is enough to put M(inf)=0 in those formulae. Also see the following reference

MD Salas JL Thomas, Far-Field Boundary Conditions for Transonic Lifting Solutions to the Euler Equations, AIAA Journal, vol. 24, no. 7, 1986
  Reply With Quote

Old   September 6, 2005, 03:10
Default Re: Farfield BC: vortex correction for lifting bod
  #3
zonexo
Guest
 
Posts: n/a
ok thanks. but has anyone used this correction before? Is it effective ie reducing the farfield location by quite a bit?

Thanks
  Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Vortex in an intake pipe, critical submergence Julien Pralong FLOW-3D 1 October 23, 2010 16:24
creating vortex core line aay023 Main CFD Forum 0 September 15, 2010 22:49
Pressure farfield vs Velocity Inlet BC DarrenC FLUENT 1 September 16, 2009 03:23
turbulent scales of forced vortex and free vortex lcw Main CFD Forum 3 September 1, 2005 14:40
Kármán vortex street in cavitating flow behind bodies in the cavitation tunnel L. Könözsy Main CFD Forum 0 April 17, 2000 14:16


All times are GMT -4. The time now is 07:04.