摘要 |
A cavity system that tends to increase the thickness (28) of the shear layer (22), comprising: a cavity (2) and a plate (104); the plate (104) comprising 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) being positioned in the proximity of a leading edge (14) of the cavity (2); the surface of the plate (104) at a perpendicular or oblique angle to the actual or intended flow direction (6). The plate (104) may be positioned at an oblique angle to the flow direction (6). One or more flow alteration elements, for example elongate members (34) positioned across the holes and/or members (38) positioned directly behind or in front of the holes (4). |