Abstract: The disclosure provides a passive pressure drag reduction apparatus. The apparatus comprises a housing (106) comprising a base face (114), an open top face (110) opposite the base face and at least one side face (108) extending between the base face and the top face, wherein the base face, the top face and the at least one side face define a cavity (102). A panel (112) is aligned with the top face of the housing, and there is provided an aperture (104) extending around the panel, wherein the cavity is in fluid communication with an environment surrounding the apparatus via the aperture. Further, attachment means are provided arranged to secure the panel to the housing.

Abstract: A drag reduction apparatus for reducing the aerodynamic drag on a bluff body with a blunt trailing edge caused by fluid flow characteristics at the wake of the bluff body, the drag reduction apparatus comprising: one or more control elements configured to be coupled to the bluff body and to move with respect to the bluff body, whereby the movement of the one or more control elements controls fluid flow at the wake of the bluff body to reduce the drag caused by fluid flow instabilities and environmental asymmetries.

Abstract: The disclosure provides a passive pressure drag reduction apparatus. The apparatus comprises a housing (106) comprising a base face (114), an open top face (110) opposite the base face and at least one side face (108) extending between the base face and the top face, wherein the base face, the top face and the at least one side face define a cavity (102). A panel (112) is aligned with the top face of the housing, and there is provided an aperture (104) extending around the panel, wherein the cavity is in fluid communication with an environment surrounding the apparatus via the aperture. Further, attachment means are provided arranged to secure the panel to the housing.

Abstract: A vehicle comprising at least one pressure-drag-reducing apparatus (1) for reducing the pressure drag on the vehicle. The apparatus comprises: a housing (31) at least partly defining a cavity (34) and an aperture (35) in the housing (31), the cavity (34) in fluid communication via the aperture (35) with the environment surrounding the vehicle; and oscillating means (32, 36) for creating an oscillation in pressure across the aperture between the cavity and the environment. The cavity volume, the frequency of oscillation, the aperture size and the amplitude of oscillation are arranged to cause fluid to be alternately drawn into, and ejected from, the cavity through the aperture. The apparatus is positioned relative to the remainder of the vehicle such that the ejected fluid entrains fluid from the environment to reduce pressure drag on the vehicle.

Abstract: A vehicle comprising at least one pressure-drag-reducing apparatus (1) for reducing the pressure drag on the vehicle. The apparatus comprises: a housing (31) at least partly defining a cavity (34) and an aperture (35) in the housing (31), the cavity (34) in fluid communication via the aperture (35) with the environment surrounding the vehicle; and oscillating means (32, 36) for creating an oscillation in pressure across the aperture between the cavity and the environment. The cavity volume, the frequency of oscillation, the aperture size and the amplitude of oscillation are arranged to cause fluid to be alternately drawn into, and ejected from, the cavity through the aperture. The apparatus is positioned relative to the remainder of the vehicle such that the ejected fluid entrains fluid from the environment to reduce pressure drag on the vehicle.