2. FlowPAC Acoustics Research Scott C. Morris Thomas J. Mueller

3. Overview Basic and applied research Mix of theoretical, computational, and experimental capabilities Experimental tools include: –Anechoic Wind Tunnel (AWT) –Phased Microphone Array –Laser vibrometry –Particle Image Velocimetry

4. Schematic of Rotor Wake Phenomena

5. Swirling Flow Phenomena

6. Wake Distortion by Swirl

7. Top View of the Acoustic Pressure of a 3D Cascade with 30 o Stagger

8. Experimental Approach: Acoustic Theory LES calculations Hot-wire & PIV measurements Far field signature Boundary Conditions Unsteady wall pressure

9. Acoustic Arrays Array Panel #1 Flow Model

10. Beamforming Results (Example SPL map) U ref = 69 ft/s Array #1 z = 42 in. Test section boundary Model trailing edge location Flow: L to R Inlet noise Trailing edge noise Collector noise

11. How well does the array work? LOW Frequency example Combined sound BF-Left BF-Right

12. Acoustic spectra: 3 regions Low frequency Vortex shedding Broadband

13. PIV Experimental Setup Trailing Edge 12-bit CCD Cameras Nd YAG Lasers Lasers Sheet Camera view areas Flow

14. Instantaneous Flow Field Resutls shadow area

15. Instantaneous vorticity contours

16. Phase averaged vorticity

17. Prediction of broadband sound

18. Current Projects Include: Trailing Edge Sound Ducted Propulsion Acoustics of very light fluid-structure interactions Window buffeting Effect of structural acoustics on dipole source strength