Cavity acoustic tones suppression

1 . A cavity system, comprising:

a cavity and a spoiler; and

the spoiler having a front surface and a rear surface,

wherein the spoiler is positioned in proximity to a leading edge of the cavity, the leading edge being relative to an actual or intended flow direction of a fluid over the cavity, the cavity having a pair of longitudinal edges, where at least a portion of the front surface continuously extends from one of the longitudinal edges in the pair of longitudinal edges to the other one of the longitudinal edges in the pair of longitudinal edges,

wherein the spoiler is arranged with its longitudinal axis perpendicular or at an oblique angle to the actual or intended flow direction such that the front surface faces towards the flow direction, and

wherein the front surface is non-planar.

2 . The cavity system according to claim 1 , wherein in transverse cross-section the front surface of the spoiler comprises a plurality of peaks and troughs.

3 . The cavity system according to claim 2 , wherein in transverse cross-section the front surface of the spoiler is sinusoidal.

4 . The cavity system according to claim 2 , wherein in transverse cross-section the front surface of the spoiler takes a zigzag form.

5 . The cavity system according to claim 4 , wherein the spoiler comprises a plurality of plates, wherein a free edge of each plate in the plurality of plates is coupled to a free edge of an adjacent plate, with an angle between 10 degrees and 170 degrees being formed between two adjoining plates, such that the plurality of plates form a zigzag.

6 . The cavity system according to claim 1 , wherein the rear surface of the spoiler matches a contour of the front surface of the spoiler.

7 . The cavity system according to claim 1 , wherein the spoiler comprises an undulating edge when viewed through a longitudinal cross-section.

8 . The cavity system according to claim 7 , wherein the undulating edge comprises a plurality of teeth.

9 . The cavity system according to claim 8 , wherein the teeth are triangular in longitudinal cross-section.

10 . The cavity system according to claim 8 , wherein at least one of the teeth is orientated such that a plane of its front surface is twisted relative to an adjacent front surface of the spoiler.

11 . The cavity system according to claim 8 , wherein a first tooth in the plurality of teeth is taller than a second tooth in the plurality of teeth.

12 . The cavity system according to claim 8 , wherein a first tooth in the plurality of teeth is arranged closer to the leading edge than a second tooth in the plurality of teeth.

13 . The cavity system according to claim 7 , wherein the undulating edge is integrally formed in an edge of spoiler opposite an edge of the spoiler proximate to the cavity.

14 . The cavity system according to claim 7 , wherein the undulating edge is offset, in the flow direction, from an edge of the spoiler opposite an edge of the spoiler proximate to the cavity.

15 . An aircraft comprising the cavity system according to claim 1 , wherein the cavity is a weapons bay.

16 . The cavity system according to claim 9 , wherein at least one of the teeth is orientated such that a plane of its front surface is twisted relative to an adjacent front surface of the spoiler.

17 . An aircraft comprising the cavity system according to claim 5 , wherein the cavity is a weapons bay.

18 . An aircraft comprising the cavity system according to claim 7 , wherein the cavity is a weapons bay.

19 . The cavity system according to claim 5 , wherein the rear surface of the spoiler matches a contour of the front surface of the spoiler.

20 . The cavity system according to claim 1 , wherein the spoiler is entirely outside the cavity.