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

CFD to analyse tip stall

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 1, 2014, 03:55
Default CFD to analyse tip stall
  #1
Member
 
Hedley
Join Date: May 2014
Posts: 52
Rep Power: 11
hedley is on a distinguished road
I have a composite plane with NACA 64212.5 root / chord 1.6 meters and a NACA 64210 tip . 3 degrees sweepback and 3 degrees washout / twist . The airplane has a tendancy to drop a wing without warning . I started off trying to understand tip stall aerodynamics and can not find one complete discussion which discusses planform , washout , renyolds number effect SO I thought I should do a CFD analysis of the wing and thought I could take the 3D model and place it in a flow field and then change the angle of attack dynamically around the stalling AOA and in realtime visualise the stall progression - modify wing profile and rinse and repeat .

1. Am I dreaming or can this be done. ?
2. Are there any complete texts on tip stalling ?
3. Does CFD work at the stall ? only 80 KTS and Reynolds number +- 4 Million depending on station .
4. I downloaded SU2 and fell into the black hole of complexity but is this solver capable of doing what I want ?
5. I realized that meshing is as important as the solver so after much assistance from Pointwise downloaded their trial meshing software which looks awesome .
6. Is there a dictionary of jargon throughout the toolchain as when asked questions I do not understand the question let alone the formulation of a response ?
7. Are there books that go through principles and the toolchain without breaking your cranium on the underlying Math ?
8. My current toolchain is - Solid Edge -> .stp 3D model -> Pointwise eval licence 30 days -> SU2 3.1 -> Paraview .
9. I worked through some examples in SU2 eg Onera M6 and get a pretty picture in Paraview but can not find an explanation of what I am looking at in the output visualisation .

In summary I was hoping to see a color shaded visualisation of the stall progression on the wing as AOA changed -I guess this is achieved by looking at the pressure gradient ? If the tip section stalls first then model a leading edge droop and continue until I get some idea of a solution . Tufting the airplane and flight testing would be a long arduous and potentially terminal .
process.

Any responses would be highly appreciated.
hedley is offline   Reply With Quote

Old   May 1, 2014, 07:26
Default
  #2
Senior Member
 
lore
Join Date: Mar 2010
Location: Italy
Posts: 460
Rep Power: 18
lovecraft22 is on a distinguished road
Send a message via Skype™ to lovecraft22
1. Yes, it can be done. Why do you have sweepback in such an airplane anyway? I would start with that probably rather than with the airfoil

3. Yes.

As for the stall, you can look at pressure, near wall velocity, skin friction, olflow…

EDIT: also trying and control the tip vortex might be of help here…

Last edited by lovecraft22; May 1, 2014 at 10:23.
lovecraft22 is offline   Reply With Quote

Old   May 1, 2014, 13:09
Default
  #3
Member
 
Hedley
Join Date: May 2014
Posts: 52
Rep Power: 11
hedley is on a distinguished road
Quote:
Originally Posted by lovecraft22 View Post
1. Yes, it can be done. Why do you have sweepback in such an airplane anyway? I would start with that probably rather than with the airfoil

3. Yes.

As for the stall, you can look at pressure, near wall velocity, skin friction, olflow…

EDIT: also trying and control the tip vortex might be of help here…
The airplane is a falcomposite furio - www.falcomposite.com nased on Italian Stelio Frati design the sweepback on leading edge is not severe but from planform view it has 1.6m root chord and 800mm tip chord . This means differing renyolds numbers across span as compared to a plank plus the thinning airfoil section hence the washout or twist . The parent of this plane is the SF260 which needed turbulators placed near tip to compensate for tip stalls that were experienced in the slow flight normally when turning finals with gear down .
hedley is offline   Reply With Quote

Old   May 1, 2014, 13:47
Default
  #4
Senior Member
 
lore
Join Date: Mar 2010
Location: Italy
Posts: 460
Rep Power: 18
lovecraft22 is on a distinguished road
Send a message via Skype™ to lovecraft22
Actually it doesn't look like the wing has a sweep angle (as would be reasonable at that cruise speed), it only features taper.
lovecraft22 is offline   Reply With Quote

Old   May 1, 2014, 14:24
Default
  #5
Member
 
Hedley
Join Date: May 2014
Posts: 52
Rep Power: 11
hedley is on a distinguished road
yes that is correct if sweep is defined as a sweepback of the 25% MAC line . thanks
hedley is offline   Reply With Quote

Old   May 1, 2014, 18:08
Default
  #6
Senior Member
 
Martin Hegedus
Join Date: Feb 2011
Posts: 500
Rep Power: 19
Martin Hegedus is on a distinguished road
Can CFD to this? Depends. How accurate do you want the results to be?

The wing tip vortex is challenging to model. I don't think there is even agreement on what type of turbulence model to use. If applicable, you'll need to decide between a turbulence model with or without a rotation correction. That puts you on the cutting edge of things.
Martin Hegedus is offline   Reply With Quote

Old   May 1, 2014, 18:12
Default
  #7
Senior Member
 
Martin Hegedus
Join Date: Feb 2011
Posts: 500
Rep Power: 19
Martin Hegedus is on a distinguished road
Oh, in general, turbulence models perform poorly under stalled conditions, and the unset of stall.
Martin Hegedus is offline   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
How to analyse vacuum flow and leak detection in Autodesk Simulation CFD? govind Main CFD Forum 1 October 31, 2012 14:10
ASME CFD Symposium, Atlanta, July 2001 Chris R. Kleijn Main CFD Forum 0 September 13, 2000 05:48
ASME CFD Symposium, Atlanta, July 2001 Chris R. Kleijn Main CFD Forum 0 August 21, 2000 05:49
Which is better to develop in-house CFD code or to buy a available CFD package. Tareq Al-shaalan Main CFD Forum 10 June 13, 1999 00:27
public CFD Code development Heinz Wilkening Main CFD Forum 38 March 5, 1999 12:44


All times are GMT -4. The time now is 08:46.