Experimental investigation of slotted wall wind tunnel test sections for low interference road vehicle testing

Low cost high quality full scale aerodynamic data for typical present day road vehicles is not available from conventional wind tunnels using solid wall test sections.;An experimental investigation of the wall interference levels of a slotted wall wind tunnel test section using three different shaped models which produced flow fields similar to those of typical road vehicles was undertaken. Wall blockage interference was determined by measuring and comparing the drag coefficients, base pressure coefficients and the groundplane pressure signatures of the five model scales for each model shape. Influence of the wall OAR on the data is also presented and demonstrates that for a properly configured test section virtually interference free measurements can be achieved passively for even models of extreme area blockage.