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May 1, 2014, 03:55 |
CFD to analyse tip stall
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#1 |
Member
Hedley
Join Date: May 2014
Posts: 52
Rep Power: 11 |
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. |
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May 1, 2014, 07:26 |
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#2 |
Senior Member
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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. |
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May 1, 2014, 13:09 |
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#3 | |
Member
Hedley
Join Date: May 2014
Posts: 52
Rep Power: 11 |
Quote:
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May 1, 2014, 13:47 |
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#4 |
Senior Member
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Actually it doesn't look like the wing has a sweep angle (as would be reasonable at that cruise speed), it only features taper.
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May 1, 2014, 14:24 |
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#5 |
Member
Hedley
Join Date: May 2014
Posts: 52
Rep Power: 11 |
yes that is correct if sweep is defined as a sweepback of the 25% MAC line . thanks
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May 1, 2014, 18:08 |
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#6 |
Senior Member
Martin Hegedus
Join Date: Feb 2011
Posts: 500
Rep Power: 19 |
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. |
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May 1, 2014, 18:12 |
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#7 |
Senior Member
Martin Hegedus
Join Date: Feb 2011
Posts: 500
Rep Power: 19 |
Oh, in general, turbulence models perform poorly under stalled conditions, and the unset of stall.
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