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Main Title Wake of a block vehicle in a shear-free boundary flow : an experimental and theoretical study /
Author Eskridge, Robert E. ; Thompson, Roger S.
Other Authors
Author Title of a Work
Thompson, Roger S.
CORP Author Environmental Sciences Research Lab., Research Triangle Park, NC.
Publisher U.S. Environmental Protection Agency, Environmental Sciences Research Laboratory,
Year Published 1982
Report Number EPA-600/3-82-007
Stock Number PB82-196528
OCLC Number 700505214
Subjects Automobiles--Motors--Exhaust gas--Mathematical models ; Wakes (Aerodynamics)
Additional Subjects Automobiles ; Exhaust emissions ; Wakes ; Flow distribution ; Aerodynamic characteristics ; Laminar flow ; Turbulent flow ; Boundary layer flow ; Flow fields
Internet Access
Description Access URL
Library Call Number Additional Info Location Last
EKBD  EPA-600/3-82-007 Research Triangle Park Library/RTP, NC 02/07/2011
NTIS  PB82-196528 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation xv, 99 p. : ill., charts ; 28 cm.
The wake of a moving vehicle was simulated using a specially-constructed wind tunnel with a moving floor. A 'block-shaped' model vehicle was fixed in position over the test-section floor while the floor moved at the freestream air speed to produce a uniform, shear-free, approach flow. This simulates an automobile traveling along a straight highway under calm atmospheric conditions. Vertical and lateral profiles of mean and fluctuating velocities and Reynolds stresses in the wake of the vehicle were obtained using a hot-film anemometer with an X-probe. Profiles were taken at distances of 10 to 80 model heights downwind. A momentum type wake was observed behind the block-shaped vehicle. The wake does not have a simple self-preserving form. However, it is possible to collapse the velocity deficit with one length and one velocity scale. Two new theories for the velocity deficit are compared to the theory of Eskridge and Hunt (1979). A theory which considered a height-dependent eddy viscosity was found to fit the data best. Length and velocity scales were found for the longitudinal variation of the turbulent kinetic energy. The lateral variation is described by a two-dimensional numerical fit of the crosswind variation of the data.
"January 1982." Includes bibliographical references (p. 24-25) "EPA-600/3-82-007."