Abstract: An apparatus for reducing aerodynamic drag on a tractor-trailer includes a panel configured to extend along a length of the trailer, the panel having first and second ends and being contoured along a lengthwise direction of the panel from the first end to the second end. Another apparatus includes a panel including a base and an array of rib-like protrusions extending outwardly from the base. Another apparatus includes a panel including an inner portion and an outer portion coupled to each other along first and second seams to define a cavity and including an air inlet for allowing air influx into the cavity from free-stream air flow during transit of the tractor-trailer to transition the panel from a retracted state to a deployed state. When in the deployed state, the panel is configured to alter an external topography of the tractor-trailer.

Abstract: An apparatus for reducing aerodynamic drag on a tractor-trailer includes a panel configured to extend along a length of the trailer, the panel having first and second ends and being contoured along a lengthwise direction of the panel from the first end to the second end. Another apparatus includes a panel including a base and an array of rib-like protrusions extending outwardly from the base. Another apparatus includes a panel including an inner portion and an outer portion coupled to each other along first and second seams to define a cavity and including an air inlet for allowing air influx into the cavity from free-stream air flow during transit of the tractor-trailer to transition the panel from a retracted state to a deployed state. When in the deployed state, the panel is configured to alter an external topography of the tractor-trailer.