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

Pressure Drag underestimated

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 26, 2008, 14:22
Default Pressure Drag underestimated
  #1
rc2v07
Guest
 
Posts: n/a
Hi again!

Im simulating a keel and bulb in water, steady at 13m/s 6 degree angle of attack. The problem is convergence only to 10*-3 and that pressure drag is greatly underestimted. Viscous drag is quite good though. I am using SST with a Y+ of 1 and lift prediction is fine. Any ideas?!

Thanks
  Reply With Quote

Old   July 26, 2008, 16:00
Default Re: Pressure Drag underestimated
  #2
Rogerio Fernandes Brito
Guest
 
Posts: n/a
Hi Sir rc2v07,

i didnīt get your computational domain. But, change the scheme? - change the mesh? (how about a hexahedrical mesh?) - increase the level of turbulence?

Whatever her merits, good lucky there!
  Reply With Quote

Old   July 28, 2008, 01:58
Default Re: Pressure Drag underestimated
  #3
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

Have you done a mesh independance check? Are you running the right rubulence model? You might need a transition turbulence model here. Are you boundaries far enough away? Have you got the inlet turbulence levels set right? Is the surface smoothness correct?

Glenn Horrocks
  Reply With Quote

Old   July 28, 2008, 17:18
Default Re: Pressure Drag underestimated
  #4
rc2v07
Guest
 
Posts: n/a
Hi Glenn,

Have done mesh independence and running SST, tried laminar and K-epsilon to get an initial values file but get overflow problem. Domain is large engough for sure. I might try transitional. Thanks
  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
UDF to define or adjust pressure??? engahmed FLUENT 0 July 6, 2010 17:19
anyone has got this paper? Al Main CFD Forum 3 October 8, 2007 02:04
Pressure Drag not calculated correctly in CFX-Post Andy CFX 5 August 2, 2006 12:06
FLOW AROUND A PLATE_NEGATIVE ABSOLUTE PRESSURE???? tania FLUENT 11 March 23, 2004 09:51
pressure. lift and drag coefficients waqar mahboob Main CFD Forum 0 July 25, 1998 03:34


All times are GMT -4. The time now is 13:27.