OK....what site was that?
Skip
At 11:45 AM 1/23/02 -0600, Albaugh, Neil wrote:
>Jim;
>
>You might look at this site for aerodynamic info. It has links to other
>sites with data on airfoils and aerodynamic analysis software.
>
>Regards, Neil Tucson, AZ
>
>
>-----Original Message-----
>From: Waldron, James [mailto:James.Waldron@CWUSA.COM]
>Sent: Monday, January 21, 2002 2:31 PM
>To: 'land-speed@autox.team.net'
>Subject: Reynolds numbers
>
>
>So, longer than I'd like to admit ago, when I studied this sort of thing in
>college, I remember that there were two components to determining how fast
>something would go on a certain amount of power. One was the sum of the
>'frictions' that had to be overcome (bearings, rolling resistance, etc.),
>and the other was the air resistance. When you were going slowly, the first
>friction was the biggest, but as you started going faster and faster air
>resistance became the dominant player. Air resistance was cubic, related to
>speed, and was determined by a 'Reynolds' number that related (it starts
>getting fuzzy here) the resistance of the shape of the object to an
>equivalent flat plate. Then something about a 1 foot square flat plate
>being some sort of standard. ANYWAY, I remember asking how Reynolds
>numbers could be determined and being told that it was way too complex to
>calculate and that most were determined experimentally by using scale models
>in wind tunnels (and for cars, further complicated by the fact that the body
>under investigation was close to the ground - not up in the sky - and the
>model ground had to move at speed to get real information, and after
>thinking about using my belt sander to simulate moving ground in the college
>aerospace model wind tunnel, and the look I got from the dean when I told
>him I wanted to put a running belt sander with 80 grit sandpaper in the wind
>tunnel and 'didn't think it could get loose'..... You get the picture.)
>So, what I want to know is, in this day of lots of computing horsepower on
>my desktop, are there any programs that can be fed a 3 dimensional object,
>can simulate air flow, and determine Reynolds numbers? And, of course, I'd
>like to play with the design on-the-fly to see what needs to be done to
>minimize the drag. Or, are we still in the days of 'take it to the salt and
>see what it will do?', record the speed and calculate to determine my own
>Reynolds number (if I still care at that point)? I know that the Americas
>Cup Yacht guys do lots of computer simulation, but also still use a scale
>model moving through a tank of water (water is a lot thicker than air, but
>except for compressibility, fluid dynamics should still apply?). Anyone
>have any sources of information?
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