Acoustic liner having internal structure

1. An acoustic liner, comprising:

a support layer having a first side and a spaced second side and where the support layer includes a set of partitioned cavities extending between the first side and the second side, defining a set of cells, and where the set of partitioned cavities have open faces;

a first facing sheet operably coupled to the support layer such that the first facing sheet overlies and closes the open faces on the second side; and

a set of internal separator structures within at least some of the set of partitioned cavities, where a single internal separator structure is located within a single cavity of the set of partitioned cavities and the single internal separator structure includes an hourglass shaped internal separator structure dividing the single cavity into three fluid cavities, the three fluid cavities include first and second fluid cavities inside of the hourglass shaped internal separator, and a third fluid cavity outside of the hourglass shaped internal separator.

2. The acoustic liner of claim 1 , further comprising a second facing sheet operably coupled to the support layer such that the second facing sheet overlies the open faces on the first side, with a set of perforations included in the second facing sheet.

3. The acoustic liner of claim 1 wherein the support layer includes a honeycomb core.

4. The acoustic liner of claim 1 wherein the set of internal separator structures are integrally formed with the support layer.

5. The acoustic liner of claim 1 wherein at least two of the three fluid cavities are fluidly coupled with each other.

6. The acoustic liner of claim 5 wherein a first fluid cavity and a second fluid cavity of the three fluid cavities are fluidly coupled via a neck of the hourglass shaped internal separator structure and at least one of the first fluid cavity and the second fluid cavity are fluidly coupled with a third fluid cavity of the three fluid cavities.

7. An acoustic liner, comprising:

a support layer having a first side and a spaced second side and where the support layer includes a set of partitioned cavities extending between the first side and the second side, defining a set of cells, and where the set of partitioned cavities have open faces;

a first facing sheet operably coupled to the support layer such that the first facing sheet overlies and closes the open faces on the second side; and

a set of internal separator structures within at least some of the set of partitioned cavities, where a single internal separator structure is located within a single cavity of the set of partitioned cavities and the single internal separator structure includes a hemispherical shaped internal separator dividing the single cavity into two fluid cavities,

wherein a base of the hemispherical shaped internal separator is adjacent the second side of the support layer, and a height of the hemispherical shaped internal separator above the base of the hemispherical shaped internal separator equals a radius of curvature of the hemispherical shaped internal separator.

8. The acoustic liner of claim 7 wherein a top of the hemispherical shaped internal separator includes a circular opening.

9. The acoustic liner of claim 7 wherein the base of the hemispherical shaped internal separator intersects at least one wall of the single cavity.

10. An aircraft engine assembly, comprising:

a nacelle configured to surround an aircraft engine and having an inlet section that defines an inlet open to ambient air and where the nacelle at least partially defines an annular airflow path through the aircraft engine assembly; and

an acoustic panel operably coupled to at least one of the aircraft engine or the nacelle, the acoustic panel comprising:

a support layer having a first side and a spaced second side and where the support layer includes a set of partitioned cavities extending between the first side and the second side, defining a set of cells, and where the set of partitioned cavities have open faces;

a first facing sheet operably coupled to the support layer such that the first facing sheet overlies and closes the open faces on the second side; and

a set of internal separator structures within at least some of the set of partitioned cavities, where a single internal separator structure is located within a single cavity of the set of partitioned cavities and the single internal separator structure includes an hourglass shaped internal separator structure dividing the single cavity into three fluid cavities, the three fluid cavities include first and second fluid cavities inside of the hourglass shaped internal separator, and a third fluid cavity outside of the hourglass shaped internal separator.

11. The aircraft engine assembly of claim 10 , further comprising a second facing sheet operably coupled to the support layer such that the second facing sheet overlies the open faces on the first side, with a set of perforations included in the second facing sheet and at least one perforation of the set of perforations fluidly coupled with the single cavity.

12. The aircraft engine assembly of claim 10 wherein the set of internal separator structures are integrally formed with the support layer.

13. An aircraft engine assembly, comprising:

a nacelle configured to surround an aircraft engine and having an inlet section that defines an inlet open to ambient air and where the nacelle at least partially defines an annular airflow path through the aircraft engine assembly; and

an acoustic panel operably coupled to at least one of the aircraft engine or the nacelle, the acoustic panel comprising:

a support layer having a first side and a spaced second side and where the support layer includes a set of partitioned cavities extending between the first side and the second side, defining a set of cells, and where the set of partitioned cavities have open faces;

a first facing sheet operably coupled to the support layer such that the first facing sheet overlies and closes the open faces on the second side; and

a set of internal separator structures within at least some of the set of partitioned cavities, where a single internal separator structure is located within a single cavity of the set of partitioned cavities and the single internal separator structure includes a hemispherical shaped internal separator dividing the single cavity into two fluid cavities,

wherein a base of the hemispherical shaped internal separator is adjacent the second side of the support layer, and a height of the hemispherical shaped internal separator above the base of the hemispherical shaped internal separator equals a radius of curvature of the hemispherical shaped internal separator.

14. The aircraft engine assembly of claim 13 wherein a top of the hemispherical shaped internal separator includes a circular opening.

15. A method of forming a portion of an acoustic liner, comprising:

forming a support layer having a first side and a spaced second side and where the support layer includes a set of partitioned cavities extending between the first side and the second side, defining a set of cells, and where the set of partitioned cavities have open faces;

separating at least one cavity of the set of partitioned cavities into a plurality of volumes that are fluidly coupled via an internal separator structure within the at least one cavity, the internal separator structure including an hourglass shaped internal separator structure dividing the single cavity into three fluid cavities, the three fluid cavities include first and second fluid cavities inside of the hourglass shaped internal separator, and a third fluid cavity outside of the hourglass shaped internal separator; and

operably coupling a facing sheet to the second side of the support layer such that the facing sheet overlies and closes the open faces on the second side.

16. The method of claim 15 wherein separating the at least one cavity comprises locating an internal separator structure within the at least one cavity.

17. The method of claim 15 wherein locating the internal separator structure includes tuning to attenuate specific frequencies by expanding the internal separator structure within the at least one cavity.

18. The method of claim 15 wherein separating the at least one cavity includes additively manufacturing or molding the internal separator structure with the support layer.

19. The method of claim 15 , further comprising operably coupling a perforated facing sheet to a first side of the support layer such that the facing sheet overlies the open faces on first side and at least one perforation of the perforated facing sheet is fluidly coupled to a cavity of the set of partitioned cavities.

20. A method of forming a portion of an acoustic liner, comprising:

forming a support layer having a first side and a spaced second side and where the support layer includes a set of partitioned cavities extending between the first side and the second side, defining a set of cells, and where the set of partitioned cavities have open faces;

separating at least one cavity of the set of partitioned cavities into a plurality of volumes that are fluidly coupled via an internal separator structure within the at least one cavity, the internal separator structure including a hemispherical shaped internal separator dividing the single cavity into two fluid cavities, a base of the hemispherical shaped internal separator being adjacent the second side of the support layer, and a height of the hemispherical shaped internal separator above the base of the hemispherical shaped internal separator being equal to a radius of curvature of the hemispherical shaped internal separator; and

operably coupling a facing sheet to the second side of the support layer such that the facing sheet overlies and closes the open faces on the second side.