CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

computational grid generation on fluent

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

LinkBack Thread Tools Display Modes
Old   February 13, 2001, 10:33
Default computational grid generation on fluent
Posts: n/a
Hi! guys,

I am a new user of fluent. I am working on a simple aerofoil shape trying to analyse the flow over it when it is near the ground. ie: ground effects

any effects if i change the grid definition? i am currently using tri elements and type ave would there be much different if i use other type of elements? I am running it on spalart-allmaras model.

what are possible ways of improvements?

could some guys who are good in such stuff.. provide so feedback

thanks alot really appreciate it


  Reply With Quote

Old   February 13, 2001, 10:51
Default Re: computational grid generation on fluent
Jonas Larsson
Posts: n/a
For airfoil flows you should definitely use quads/hexas (if your geometry allows that). This will resolve the boundary-layers and wakes better since you can assure that the cells are aligned with the flow. The 1-equation SA model is okay for attached flows in this type of applications.
  Reply With Quote

Old   February 13, 2001, 11:18
Default Re: computational grid generation on fluent
Posts: n/a
Hi! Jonas

Thanks for the response

appreciate it, but if we are considering just the forces for life and drag over the foil, what are some of the concerns that we should look out for? its a one dimensional problem and we are using high reynolds number, is it still suitable to use a turbulence model like the SA? its steady state flow... at 50m/s across the aerofoil.

thanks again Terry
  Reply With Quote

Old   February 13, 2001, 11:33
Default Re: computational grid generation on fluent
Jonas Larsson
Posts: n/a
Computing the drag correctly can be a bit tricky since you have to get the skin-friction correct. The lift is easier. I haven't done any validations of the SA model for airfoils so I can't say how well it will perform on the drag. You can always compare it to a more advanced two-equation model (I'd recommend the Realizable k-epsilon model with the Wolfstein 1-eq model in the boundary layers - Fluent calls it "two-layer zonal model"). Lift should be okay as long as you have attached flow. If this is an airfoil in free air make sure you use a very large domain, this is important. Search the forums here and you'll find a lot of discussion about this, including references, if my memory doesn't fail me now.

You should of course first compute a wing for which you have data to compare your results with - see the Resources/Reference section for a lot of nice cases to run. I think that both the ERCOFTAC database and the NPARC database includes airfoil cases.
  Reply With Quote


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
HELP! grid check failed in parallel fluent restart FLUENT 0 March 5, 2011 10:55
Fluent, Grid Builing Issue Mark FLUENT 4 March 14, 2008 16:24
Exporting ICEM Tetra Grid to Fluent with Hexa-Core Tim FLUENT 2 August 30, 2007 07:16
Help Re. Grid Generation Patel Amit R. FLUENT 1 February 28, 2003 22:27
Grid Independent Solution Chuck Leakeas Main CFD Forum 2 May 26, 2000 11:18

All times are GMT -4. The time now is 20:28.