RE: Wind Tunnel Design and RP models

Date: Fri Apr 30 1999 - 10:43:49 EEST

Very, very simply a slotted wall wind tunnel is one where horizontal
slots run along the length of the test section walls (where the test
model is positioned). As air passes over a vehicle it expands. On the
road (for example) the air is not constrained so expands freely, or put
another way, the blockage ratio is zero (the ratio of model area to
test section area). But in a wind tunnel solid walls constrain the air
stream, and if the test section is too small (a high blockage ratio) it
can subject the vehicle to exaggerated high air speeds over localised
areas. The object of slotted walls is to allow the air to expand around
a vehicle whilst having a small test section.

In terms of running costs, a small wind tunnel is cheaper to run as the
power requirements are less.

Steve Windsor
Rapid Prototyping & Tooling
Rover Group
University of Warwick
Gibbet Hill Road
Coventry, UK

Tel + 44 1203 524907
Fax +44 1203 524878


-----Original Message-----
From: SiderWhite
Sent: Thursday, April 29, 1999 1:10 AM
To: rp-ml
Cc: SiderWhite
Subject: Wind Tunnel Design and RP models

Dear rp-ml:

Just read an article (obtained from Stratasys at )
Chrysler Corporation and their use of Genisys 3D printed parts for
aerodynamic design testing. At the end of the article they were
Chrysler's Aero/Thermal Development lab's wind tunnel and stated that
"rather than using the conventional solid-wall design, Chrysler built a
tunnel with a slotted wall. This type of tunnel is less expensive to
construct and operate, but it still provides high-quality data."

An "affordable" wind tunnel for the masses? Can somebody enlighten me
as to
what a "slotted wall" wind tunnel design is? And what the cost to
one of these is vs. a conventional solid wall?
Maybe some of our Chrysler friends will be reading this....

Best Regards,

Glenn Whiteside

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