Quote:
Originally Posted by Piotrsko
I see this as a moving collection of variable conditions which may or may not average out. Then there is the "laminar" body.......what part of this body is laminar and how much of the turbulent aft is going to affect data since I have yet to see any shape 100% laminar. I can see a very low drag shape getting consistent data but that is the limit, I believe. I also envision the reynolds number wandering around since race tracks have straight-a-ways to go fast on and tight turns to slow on which will affect the turbulence unless you pick a slow enough speed as to not accelerate or brake.
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Good points!
* 'laminar' is really an oxymoron.
* There's no such thing.
* What passes for 'laminar' is, a surface of laminar boundary layer, up until the flow experiences the first minimum pressure, at maximum body cross-section, then from there to the trailing edges it's all an adverse pressure gradient where it's impossible for a LBL to exist, and the transition to TBL happens immediately downstream of this maximum thickness.
* The context of 'laminar' bodies as seen at SHELL Eco Marathon, SAE, and World Solar Challenge events lies within the frontal area ( from which Reynolds number is directly associated ) and 'race' velocities, which are typically quite low. And 'calm' conditions.
* And yes, the Rn will vary with velocity. 15-mph ( burn-and- coast ) average speeds are not uncommon, and a 22-mph upper limit according to rulebook.