Last math for 1998, I promise.
1) Mike's first point - The Reynolds Number is:
Re = {(rho) * (v) * d} / (mu)
where
rho is density of the air ( = to 2.7 * P/T, with pressure in psia and temp
in degrees rankine {deg R = deg F +460})
v = velocity
mu = kinematic viscosity of the air (varies slightly with temp)
2) Mike's 2nd point - "Straightness" = laminar flow, which is typically
considered to be Reynold's number less than 3,000.
You really want to make sure your tunnel provides a repeatable source flow
of air with evenly distributed lines in the flow field (representing a nice
even pressure delivery).
----------
> From: Mike Gigante <mikeg@vicnet.net.au>
> To: David Ramsey <dwramsey@worldnet.att.net>; Daniel1312@aol.com
> Cc: spridgets@autox.team.net
> Subject: Re: Wind tunnel access
> Date: Monday, December 14, 1998 12:47 PM
>
> If you do decide to use scale models and a home built tunnel,
> there are a couple of important things to take care of.
>
> 1) Reynolds Number (size, density, airspeed, viscosity all combine
> to make a scale model act the same (aerodynamically) as the full
> size.
>
> 2) "straightness" of the air. Baffles and honeycomb (in-line) are used to
> reduce the turbulence and vorticity of the air.
>
> If you want to be *really* fancy, you could include a rolling road as
part
> of the tunnel.
>
> Of course if you just want a faster sprite, why not buy the sebring coupe
> replica kit from Brian Archer. It's aerodynamics would be a lot better
> than stock and it is a purdy little thing.
>
> Mike
>
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