I just spent a couple of hours during a flight back from the east re-reading some of Goro Tamai's book "The Leading Edge" specifically about Reynolds numbers and the transition from laminar to turbulent air flow and got to thinking about how this applies to air scoops and the velocity of air through them. Looking at this information it becomes appearent that it is VERY IMPORTANT to start expanding the diameter of the inlet path right after the inlet opening because if you are going say 200 mph and you have an inlet opening of lets say 5 inch diameter and if that diameter is held for too long say even 5 inches the air will transition from laminar, assuming that you picked in an area that is laminar flow, to turbulent at which time the thickness of the boundry layer begins to thicken very rapidly and starts to choke off the effectiveness of the scoop. I think this is why you see air inlets on F1 cars with an almost abrupt transition from the inlet to a very large plenum which I would speculate drops the air velocity to a level such that the reynolds number is low enough to provide laminar flow from which additional inlet pressure can be obtained per Danny Bernoulli's formula, which really applies best to laminar flow.
That's my two cents worth, any comments?
I've read a lot of that book, but a lot of it is over my head. I just go to the conclusions and figure they have it right
Rex I think your math skills are way better than mine. In college I got Thur calculus then went in the service and when I went back to school they said the year I had taken was now only worth 1 semesters credit. I had to take more and barely made it through. I guess I was more interesting in riding my motorcycle around in the mountains outside of Laramie. Now I wish I would have applied myself a little more. I still have the text book and keep telling myself it isn't too late to try and get through it, but I'll probably still be saying that the day I die
c ya, Sum