Would hesitate to make that assumption. Would rather say that is a secondary function of it. Honestly doesn't take very long for airflow to reattach to a wing once the wing is brought back into its operating range. If you have ever flown a small plane and then stalled it. Almost as soon as you put the nose down you can feel the wing starting to work again and providing lift.Holm86 wrote:Seems like all the 'experts' agree with me that the tubercles is there to reattach the boundary layer when drs has been activated.
It can take long enough. A delay in re-attachment of airflow was one of the reasons the F2012 struggled so much especially on corner entry. I'm not saying this is the only benefit of the tubercles, but I think it's safe to say it's one of the main reasons it was introduced.trinidefender wrote:
Would hesitate to make that assumption. Would rather say that is a secondary function of it. Honestly doesn't take very long for airflow to reattach to a wing once the wing is brought back into its operating range..
That would make sense for the F2012. However do you think the McLaren is considered one of the more unstable cars under braking for this to be a main design condition for the new rear wing? I haven't had the chance to watch many of the races this year so i wouldn't be able to judge properly.Crucial_Xtreme wrote:It can take long enough. A delay in re-attachment of airflow was one of the reasons the F2012 struggled so much especially on corner entry. I'm not saying this is the only benefit of the tubercles, but I think it's safe to say it's one of the main reasons it was introduced.trinidefender wrote:
Would hesitate to make that assumption. Would rather say that is a secondary function of it. Honestly doesn't take very long for airflow to reattach to a wing once the wing is brought back into its operating range..
Following live.timing on skysports during FP2 in Hungary, one of the conclusions of the moderatos was this: "the improved Mclaren is one of the most stable cars under braking"trinidefender wrote:That would make sense for the F2012. However do you think the McLaren is considered one of the more unstable cars under braking for this to be a main design condition for the new rear wing? I haven't had the chance to watch many of the races this year so i wouldn't be able to judge properly.Crucial_Xtreme wrote:It can take long enough. A delay in re-attachment of airflow was one of the reasons the F2012 struggled so much especially on corner entry. I'm not saying this is the only benefit of the tubercles, but I think it's safe to say it's one of the main reasons it was introduced.trinidefender wrote:
Would hesitate to make that assumption. Would rather say that is a secondary function of it. Honestly doesn't take very long for airflow to reattach to a wing once the wing is brought back into its operating range..
Light aircraft wings are different from the highly cambered wings F1 cars use. Wings like this sometimes exhibit significant "hysteresis", in which if you angle it past stall and then reduce the angle of attack, it doesn't fully regain it's original performance. If you look at the wind tunnel test data from the UIUC airfoil database, some of the high-lift airfoils exhibit this.trinidefender wrote:Would hesitate to make that assumption. Would rather say that is a secondary function of it. Honestly doesn't take very long for airflow to reattach to a wing once the wing is brought back into its operating range. If you have ever flown a small plane and then stalled it. Almost as soon as you put the nose down you can feel the wing starting to work again and providing lift.Holm86 wrote:Seems like all the 'experts' agree with me that the tubercles is there to reattach the boundary layer when drs has been activated.
There are better ways of reducing spanwise flow, and running higher angle of attack would only be helpful on the high downforce tracks, although they probably do allow that.trinidefender wrote: Therefore it makes sense that the bumps are there for a different function such as reducing spanwise flow and to allow the wing to run at a higher angle of attack.
Yes I have heard what you are saying to be true about sometimes it takes a bit for flow to re-attach to wings once brought back in to their operating range on highly cambered wings so that is very probable. However what strikes me as odd was that if it were this large a problem then you would see drivers up and down the pit lane complaining of horrible braking stability however since the introduction of DRS you don't hear this much more than you did before indicating that DRS isn't disrupting re-attachment of airflow to much.Lycoming wrote:Light aircraft wings are different from the highly cambered wings F1 cars use. Wings like this sometimes exhibit significant "hysteresis", in which if you angle it past stall and then reduce the angle of attack, it doesn't fully regain it's original performance. If you look at the wind tunnel test data from the UIUC airfoil database, some of the high-lift airfoils exhibit this.trinidefender wrote:Would hesitate to make that assumption. Would rather say that is a secondary function of it. Honestly doesn't take very long for airflow to reattach to a wing once the wing is brought back into its operating range. If you have ever flown a small plane and then stalled it. Almost as soon as you put the nose down you can feel the wing starting to work again and providing lift.Holm86 wrote:Seems like all the 'experts' agree with me that the tubercles is there to reattach the boundary layer when drs has been activated.
Of course that's not necessarily the only reason they're there, but just pointing out that reattachment is not necessarily all that quick.
There are better ways of reducing spanwise flow, and running higher angle of attack would only be helpful on the high downforce tracks, although they probably do allow that.trinidefender wrote: Therefore it makes sense that the bumps are there for a different function such as reducing spanwise flow and to allow the wing to run at a higher angle of attack.
Characterization and Design of Tubercle Leading-Edge Wings [2012] wrote: By interpreting the skin friction lines in the separation region in terms of critical points we were able to
infer that tubercles built by chord variations and constant thickness act as vortex generators. On periodic
wings they tend to reduce Clmax but mitigate the stall, by sustaining higher levels of lift for higher angles
of attack. Tubercles may be used successfully to energize the flow at critical span-wise locations, potentially
improving the outboard stall characteristics as in the case of Miklosovic’s whale flipper model. Our results
confirm Hensen’s observation that tubercles might be detrimental at low Reynolds numbers.
We have also shown that a variation in thickness along the span, which creates channels of sorts along the
chord, can be used to break up the separation regions and create spanwise fences, which can increase Clmax.
Our observations indicate that a fully three-dimesional shape optimization is necessary to design tubercles
with higher performance; this is the subject of our ongoing research. Also, recalling that the humpback is
known for performing tight turn maneuvering, an in depth assessment of tubercle performance in dynamic
stall conditions seems de rigueur.
Also remember that the lower portion of their rear wing end plates are much smaller than most teams because of their weird suspension arms. Probably means that more force has to be taken by the rear wing support and maybe a swan neck simply can't support that.Thatsnotgonewell wrote:I'm a little surprised with all this work on rear wing details that McLaren are still using a simple center support spar rather than a swan neck. Maybe they were looking for consistency rather than pure performance?