Acoustic treatment in an unducted area of a geared turbomachine

1. A geared turbomachine assembly, comprising:

an acoustic treatment that is in an unducted area of a geared turbomachine, wherein a portion of the acoustic treatment is axially aligned with a low-pressure turbine section of the geared turbomachine, wherein the acoustic treatment extends continuously from a ducted area to the portion that is axially aligned with the low-pressure turbine section of the geared turbomachine.

2. The geared turbomachine assembly of claim 1 , wherein the acoustic treatment forms a portion of a core engine cowl, wherein the acoustic treatment extends axially to an aftmost end of the core engine cowl.

3. The geared turbomachine assembly of claim 2 , wherein the acoustic treatment extends continuously from the ducted area to the aftmost end.

4. The geared turbomachine assembly of claim 2 , wherein the acoustic treatment forms a portion of the core engine cowl that provides a radially outer boundary of a core flowpath of the geared turbomachine.

5. The geared turbomachine assembly of claim 2 , wherein the acoustic treatment forms a portion of the core engine cowl that provides a radially inner boundary of a bypass flowpath of the geared turbomachine.

6. The geared turbomachine assembly of claim 2 , wherein the acoustic treatment comprises a perforated face sheet having an open area density that is from 4% to 30%.

7. The geared turbomachine assembly of claim 2 , wherein the acoustic treatment comprises a microperforated face sheet having apertures with a diameter that is less than 25 percent of a thickness of the microperforated face sheet.

8. The geared turbomachine assembly of claim 2 , wherein the geared turbomachine assembly has a fan pressure ratio less than 1.45.

9. The geared turbomachine assembly of claim 1 , wherein the acoustic treatment forms a portion of a core engine cowl that provides a radially outer boundary of a core engine flowpath of the geared turbomachine.

10. The geared turbomachine assembly of claim 1 , wherein the acoustic treatment forms a portion of a core engine cowl that provides a radially inner boundary of a bypass flowpath of the geared turbomachine.

11. The geared turbomachine assembly of claim 1 , wherein a portion of the acoustic treatment is axially aft a fan cowl of the geared turbomachine.

12. The geared turbomachine assembly of claim 1 , wherein the acoustic treatment extends continuously from the ducted area to an aftmost end of a core engine cowl.

13. The geared turbomachine assembly of claim 1 , wherein the acoustic treatment comprises a perforated face sheet having an open area density that is from 4% to 30%.

14. The geared turbomachine assembly of claim 1 , wherein the acoustic treatment comprises a microperforated face sheet having apertures with a diameter that is less than 25 percent of a thickness of the microperforated face sheet.

15. The geared turbomachine assembly of claim 1 , wherein the geared turbomachine assembly has a fan pressure ratio less than 1.45.