A computational fluid dynamics (CFD) code has been combined with a genetic algorithm (GA) to perform a two-dimensional drag minimization on the base region of tractor trailers. Few studies have been conducted with CFD driven by a GA due to extensive run times and the general non autonomous characteristics of meshing a suitable CFD geometry. This study solves the two-dimensional Reynolds-average...

Aerodynamic drag is an important factor in vehicles fuel consumption. Pressure drag which is the main component of total drag is a result of boundary layer separation from vehicle surface. Flow control methods are applied to avoid or at least delay separation. Depending upon whether these methods consume energy to control the flow or not, they are called active or passive control methods. In th...

This work investigates the ability of Coanda jet blowing to modify the base pressure of a cylindrical body aligned axially in a flow, and thereby, produce overall drag reduction. It is found that blowing through one or two slot jets concentric to the outer body circumference can significantly influence the entire base flow region. The recirculating wake is eliminated and is replaced by freestre...

Active drag reduction of an Ahmed model with a slant angle of 25o is experimentally investigated based on a combination of steady blowing over the rear window and behind the vertical base. The Reynolds number Re examined is 0.9 × 10 2.7 × 10. Steady blowing S1 was applied along the upper edge of the rear window, which has been demonstrated to be effective in suppressing the recirculation bubble...

this paper is a computational study of the behavior of aerodynamics  characteristics of an airfoil with blunt trailing edge and  studies the effects aerodynamic performance caused by modifications made to the trailing edge. blunt trailing edge airfoils are of interest in the engineering of large wind turbine blades because they allow for a strong structure with a high aerodynamic lift to struct...

there are different methods to reduce drag in high speed hulls. one of these methods is a change in the shape of the body by adding longitudinal side tunnels. in this paper it has been attempted to determine the influence of the tunnel height on hydrodynamic characteristics of the hull to achieving an optimum shape for the tunnel. to achieve this purpose, numerical simulation of the problem has...

SUMMARY A systematic sex-188 of twin-jet afterbodaes all terminating at the jet-exit has been tested at Mach numbers from M = 0.7 to 1.3 on a strut-mounted rig employing high pressure air for the Jet streams. The afterbody drag was derived from balance measurements of thrust-minus-drag and wind-off calibrations of thrust, and interpreted with the help of pressure plotting data. Two single-nozzl...