| 摘要 |
A cavity system comprising a cavity 2 and a plate 104 is arranged to increase the thickness 28 of the shear layer 22. The plate 104 comprises a plurality of holes 4 through it, wherein the proportion of the area of the plate 104 taken up by the holes is ≥ 60%, for example ≥ 75% or ≥ 90%. The plate 104 is positioned in the proximity of a leading edge 14 of the cavity 2. The plate 104 may be positioned perpendicular to, or at an oblique angle to, the actual or intended flow direction 6. One or more flow alteration elements, for example elongate members (34, figs 4-6) positioned across the holes and/or members (38, fig 7) positioned directly behind or in front of the holes 4, may form part of the plate. The system is intended for use on vehicles such as aircraft having weapon or undercarriage bays as a means to reduce in-flight noise. However, the system could also be used on other vehicles such a missile or any land vehicle such as a car or lorry or a sea-going vessel such as a ship or a submarine. |
