Search Results

Simple devices have been shown to be capable of tailoring the flow field around a vehicle and reducing aerodynamic drag. An experimental and computational investigation of a drag reduction device for bluff bodies in ground proximity has been conducted. The main goal of the research is to gain a better understanding of the drag reduction mechanisms in bluff-body square-back geometries. In principle, the device modifies the flow field behind the test model by disturbing the shear layer. As a consequence, the closure of the wake is altered and reductions in aerodynamic drag of more than 20 percent are observed. We report unsteady base pressure, hot-wire velocity fluctuations and Particle Image Velocimetry (PIV) measurements of the near wake of the two models (baseline and the modified models). In addition, the flows around the two configurations are simulated using the Reynolds Averaged Navier-Stokes (RANS) equations in conjunction with the V2F turbulence model.

The objective behind this effort is rapid aerodynamic development of vehicle themes, in the early stages of vehicle development. This paper describes a process that is suitable for the development of two-volume (or two-box) vehicle shapes (such as station wagons, minivans or sports utility vehicles). Traditionally, aerodynamic development at this stage is accomplished using wind-tunnel tests of full or partial scale test models or relying on simulations of aerodynamics employing computational fluid dyanmics (CFD). In either case, the process is not particularly effective in sustaining the desired level of communication between designers (engaged in styling activities) and engineers (engaged in packaging and aerodynamics). A key drawback here is the delay in the generation of aerodynamic drag estimates for the proposals under consideration through use of wind-tunnel tests or CFD computations.