Research under earlier Phase I and Phase II SBIR awards to Continuum Dynamics showed that the addition of fixed panels to the rear of a tractor-trailer rig reduced air drag by 10% and suggested that reductions as large as 25% might be achievable. The current Phase I SBIR award aims at identifying drag reduction devices which are retractable, stowable, and which approach a 20% reduction in air drag. Various geometries will be tested on a modified passenger van. Measurements will include wind speed and direction, ground speed of the vehicle, and pressure distribution over the aft region of the van. In addition, high speed films will be made to reveal overall flow patterns. It is estimated that reduction of air drag by 20% for the nation's existing trailer fleet would save 2 billion gallons of diesel fuel a year. The associated favorable impact on the US fuel usage and air quality would be considerable.
