Cavity acoustic tones suppression

Patent metadata

Field	Value
Publication number	US-9493233-B2
Application number	US-201414776115-A
Country	US
Kind code	B2
Filing date	Mar 13, 2014
Priority date	Mar 15, 2013
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

A cavity system that tends to increase the thickness ( 28 ) of the shear layer ( 22 ), comprising: a cavity ( 2 ) and a plurality of rods ( 4 ), for example between two and six rods; the rods ( 4 ) are positioned in the proximity of a leading edge ( 14 ) of the cavity ( 2 ) and extending across at least a part of a width of the cavity ( 2 ) in a perpendicular or oblique angle to the actual or intended flow direction ( 6 ). One or more of the rods ( 4 ) may be positioned further along the flow direction ( 6 ) compared to one or more of the other rods ( 4 ), for example to provide a zig-zag pattern of rod positions. One or more flow alteration elements ( 34, 38 ), for example channels ( 34 ) passing through the rods ( 4 ) and/or protrusions ( 38 ) extending from the rods ( 4 ), may be provided on one or more of the rods ( 4 ).

First claim

What is claimed is:

1. A cavity system, comprising:
a cavity ( 2 ) and a plurality of rods ( 4 );
the rods ( 4 ) are positioned in the proximity of a leading edge ( 14 ) of the cavity ( 2 ), the leading edge ( 14 ) being relative to an actual or intended flow direction ( 6 ) of a fluid over the cavity ( 2 );
each of the rods ( 4 ) extending lengthwise across at least a part of a width of the cavity ( 2 ) in a perpendicular or oblique angle to the actual or intended flow direction ( 6 );
wherein one or more of the rods ( 4 ) is positioned further along the flow direction ( 6 ) compared to one or more of the other rods ( 4 ); and
wherein the positioning of one or more of the rods ( 4 ) further along the flow direction ( 6 ) compared to one or more of the other rods ( 4 ) provides a zig-zag pattern of rod positions.

2. The cavity system according to claim 1 , wherein all the rods ( 4 ) are downstream of the leading edge ( 14 ).

3. The cavity system according to claim 1 , wherein the rods ( 4 ) are positioned at a distance from the leading edge ( 14 ) that is ≦0.2×the distance between the leading edge ( 14 ) and an aft edge ( 16 ).

4. The cavity system according to claim 3 , wherein the rods ( 4 ) are positioned at a distance from the leading edge ( 14 ) that is ≦0.1×the distance between the leading edge ( 14 ) and the aft edge ( 16 ).

5. The cavity system according to claim 4 , wherein the rods ( 4 ) are positioned at a distance from the leading edge ( 14 ) that is ≦0.05×the distance between the leading edge ( 14 ) and the aft edge ( 16 ).

6. The cavity system according to claim 1 , wherein the number (n) of rods in the plurality is 2≦n≦6.

7. The cavity system according to claim 6 , wherein the number (n) of rods in the plurality is 3≦n≦6.

8. The cavity system according to claim 1 , wherein the effect of the rods ( 4 ) is to increase the thickness ( 28 ) of the shear layer ( 22 ).

9. The cavity system according to claim 1 , wherein one or more flow alteration elements ( 34 , 38 ) are provided on one or more of the rods ( 4 ).

10. The cavity system according to claim 1 , wherein at least some of the flow alteration elements ( 34 , 38 ) comprise a protrusion ( 38 ) extending from the rod ( 4 ).

11. The cavity system according to claim 1 , wherein the flow alteration elements ( 34 , 38 ) are at different positions along the rod ( 4 ) on different rods ( 4 ).

12. The cavity system according to claim 1 , wherein at least two different types of flow alteration elements ( 34 , 38 ) are provided.

13. A cavity system, comprising:
a cavity ( 2 ) and a plurality of rods ( 4 );
the rods ( 4 ) are positioned in the proximity of a leading edge ( 14 ) of the cavity ( 2 ), the leading edge ( 14 ) being relative to an actual or intended flow direction ( 6 ) of a fluid over the cavity ( 2 );
each of the rods ( 4 ) extending lengthwise across at least a part of a width of the cavity ( 2 ) in a perpendicular or oblique angle to the actual or intended flow direction ( 6 );
wherein one or more flow alteration elements ( 34 , 38 ) are provided on one or more of the rods ( 4 ); and
wherein at least some of the flow alteration elements ( 34 , 38 ) comprise a channel ( 34 ) passing through the rod ( 4 ).

14. The cavity system according to claim 13 , wherein at least some of the flow alteration elements ( 34 , 38 ) comprise or provide additional edges at the one or more rods ( 4 ) that are in addition to the edge or edges provided by the underlying shape of the rod or rods ( 4 ).

15. The cavity system according to claim 13 , wherein at least some of the flow alteration elements ( 34 , 38 ) comprise a protrusion ( 38 ) extending from the rod ( 4 ).

16. The cavity system according to claim 13 , wherein the flow alteration elements ( 34 , 38 ) are at different positions along the rod ( 4 ) on different rods ( 4 ).

17. The cavity system according to claim 13 , wherein at least two different types of flow alteration elements ( 34 , 38 ) are provided.

18. A cavity system, comprising:
a cavity ( 2 ) and a plurality of rods ( 4 );
the rods ( 4 ) are positioned in the proximity of a leading edge ( 14 ) of the cavity ( 2 ), the leading edge ( 14 ) being relative to an actual or intended flow direction ( 6 ) of a fluid over the cavity ( 2 );
each of the rods ( 4 ) extending lengthwise across at least a part of a width of the cavity ( 2 ) in a perpendicular or oblique angle to the actual or intended flow direction ( 6 );
wherein one or more of the rods ( 4 ) is positioned further along the flow direction ( 6 ) compared to one or more of the other rods ( 4 );
wherein the positioning of one or more of the rods ( 4 ) further along the flow direction ( 6 ) compared to one or more of the other rods ( 4 ) provides a zig-zag pattern of rod positions;
wherein one or more flow alteration elements ( 34 , 38 ) are provided on one or more of the rods ( 4 ); and
wherein at least some of the flow alteration elements ( 34 , 38 ) comprise a channel ( 34 ) passing through the rod ( 4 ).

19. The cavity system according to claim 18 , wherein the flow alteration elements ( 34 , 38 ) are at different positions along the rod ( 4 ) on different rods ( 4 ).

20. The cavity system according to claim 18 , wherein at least two different types of flow alteration elements ( 34 , 38 ) are provided.

Assignees

• Bae Systems Plc

Inventors

• Patience David Euan

Classifications

• B64C23/005 Primary

  by other means not covered by groups B64C23/02 - B64C23/08, e.g. by electric charges, magnetic panels, piezoelectric elements, static charges or ultrasounds · CPC title

• B64C2230/08

  by influencing fluid flow by means of surface cavities, i.e. net fluid flow is null · CPC title

• F15D1/12

  by influencing the boundary layer · CPC title

• F15D1/0025

  using passive means, i.e. without external energy supply · CPC title

• B64C23/06

  by generating vortices · CPC title