||Experimental and Theoretical Study of the Wake of a Block-Shaped Vehicle in a Shear-Free Boundary Flow.
Eskridge, Robert E. ;
Thompson, Roger S. ;
||Environmental Sciences Research Lab., Research Triangle Park, NC.
Exhaust emissions ;
Air pollution ;
Motor vehicles ;
Wind tunnels ;
Test chambers ;
Atmospheric boundary layers ;
||Some EPA libraries have a fiche copy filed under the call number shown.
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. 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.