Measurement of Reference Dynamic Pressure in Open-Jet Automotive Wind Tunnels University of Stuttgart

Format:

Conference/Event

Author/Creator:

Kuenstner, Rudi, author.

Conference Name:

International Congress & Exposition (1992-02-24 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 1992

Summary:

In automotive open-jet wind tunnels reference velocity is usually measured in terms of a static pressure difference between two different cross-sectional areas of the tunnel. Most commonly used are two sections within the nozzle (Method 1: ΔP-Nozzle). Sometimes, the reference velocity is deduced from the static pressure difference between settling chamber and plenum (Method 2: ΔP-Plenum).Investigations in three full-scale open-jet automotive wind tunnels have clearly shown that determination of reference dynamic pressure according to ΔP-Plenum is physically incorrect. Basically, all aerodynamic coefficients, including drag coefficient, obtained by this method are too low. For test objects like cars and vans it was found that the error ΔcD depends on the test object's drag blockage in an open-jet wind tunnel. On the other hand, correct determination of dynamic pressure according to ΔP-Nozzle for car and van testing requires at least a certain minimum distance from balance center to reference-tap location upstream of the nozzle exit

Notes:

Vendor supplied data

Publisher Number:

920344

Access Restriction:

Restricted for use by site license