Cavity acoustic tones suppression

A cavity system for use on a vehicle, comprising:

• a cavity having at least one of a front edge and a rear edge arranged orthogonally to the actual or intended direction of travel of the vehicle, and longitudinal edges, the front and/or rear and longitudinal edges defining an opening;
• and
• at least one shock stabiliser protruding from a surface adjacent each longitudinal edge of the cavity into an ambient flow outside of the cavity, the at least one shock stabiliser comprising an inboard surface facing toward the cavity, a front surface facing toward the actual or intended direction of travel of the vehicle, and a rear surface facing away from the actual or intended direction of travel of the vehicle, wherein the front surface and the rear surface are inclined from their bases toward each other and coupled to respective edges of the inboard surface.