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Old 7th May 2011 | 20:48
  #12 (permalink)  
Pugilistic Animus
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Joined: Dec 2006
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From: The No Transgression Zone
Just a brief glance at the page it looks almost like higher reynolds numbers would lead to the airflow at the stagnation points taking longer as you go rearwards to "de-stagnify" and go back up to normal speeds. A lot of turbulence I'm sure would ensue as well.
well despite the mechanistic reasons, from continuity and conservation of energy and momentum, for either laminar and turbulent flow separation...Flow separation points are very important to attempt to predict, but because of Reynold's number effects, prediction of such terms as the skin friction drag and pitching moment coefficient.

all of these items are very very difficult to predict with theory due to slip, when speaking about very high speed flight at the usual very high altitudes....Reynold's number effect and Mach number effects are intertwined in a horribly complex way...

How would that occur? High pressure zones occurring in key areas due to the airflow stagnating and not accelerating back up?
Also,
at very very high altitudes the mean free path of the air molecules at a constant Mach or a constant dynamic pressure may exceed the span by such a factor that the boundary layer moves, continuity is lost because the boundary layer is no longer in a steady state flow respective to the wing section......slipping with the wing....even as of today theoretical treatment alone fails to make good predictions of laminar and turbulent separation points and shear effect skin friction coefficients when there is 'slip' ... not a stationary boundary layer as the theoretical treatments propose...and just as a reminder when comparing different forms it is important [due to the scale effects you mentioned] to always compare different sections and planforms at the same Rn and Mach number...otherwise the results are nonsense...

You mean hot spots on the plane?
something like that...

Still, I thought the whole purpose of a wave-rider is to produce an aircraft that can get high L/D ratios while at high mach (where it is harder to do so)

Still, I thought the whole purpose of a wave-rider is to produce an aircraft that can get high L/D ratios while at high mach (where it is harder to do so)


Robyn
Just like Puerto Ricans the designers have their 'reasons'...

I think you would have been great on a design team back in the 50's or early 60's...

Last edited by Pugilistic Animus; 7th May 2011 at 22:15. Reason: more coherent--I think
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