Aeroacoustic Investigations on a Cold Jet by Means of Simultaneous PIV and Microphone Measurements

Simultaneous PIV and microphone measurements have been performed on a cold jet at three different Mach-numbers from M = 0.5 to M = 0.9. The measurements were conducted in a synchronized manner so as to enable the calculation of the cross-correlation between the acoustic pressure and flow quantities derived from the measured velocity uctuations. 10, 000 PIV snapshots per field of view have been recorded. The main idea of the concept presented here was to use the coeffcient matrix obtained from the aforementioned correlation to identify regularities in the near-field fluctuations that are related to the radiated sound field. Results will be presented for the M = 0.5 case and a microphone positioned at an angle of 35° to the jet-axis.

[1]  H. S. Ribner,et al.  Direct Correlation of Fluctuating Lift with Radiated Sound for an Airfoil in Turbulent Flow , 1969 .

[2]  Thomas E. Siddon.  Surface dipole strength by cross‐correlation method , 1973 .

[3]  M. Samimy,et al.  Noise Sources in Controlled High Reynolds Number and High Speed Jets , 2006 .

[4]  Brian S. Thurow,et al.  Exploring Noise Sources Using Simultaneous Acoustic Measurements and Real-Time Flow Visualizations in Jets , 2002 .

[5]  W. Meecham,et al.  Determination of lip noise by correlation measurements , 1974 .

[6]  H. S. Ribner,et al.  Quadrupole correlations governing the pattern of jet noise , 1967, Journal of Fluid Mechanics.

[7]  M. Schaffar,et al.  Direct measurements of the correlation between axial in-jet velocity fluctuations and far field noise near the axis of a cold jet , 1979 .

[8]  Michel Stanislas,et al.  Main results of the Second International PIV Challenge , 2005 .

[9]  H. Ribner,et al.  Direct Correlation of Noise and Flow of a Jet , 1972 .

[10]  Lars Koop,et al.  Simultaneous Multiplane PIV and Microphone Array Measurements on a Rod-Airfoil Configuration , 2009 .

[11]  T. E. Siddon,et al.  Causality correlation analysis of flow noise with fluid dilatation as source fluctuation , 1972 .

[12]  Lars Koop,et al.  Investigation of aeroacoustic noise generation by simultaneous particle image velocimetry and microphone measurements , 2008 .

[13]  K. A. Elam,et al.  Investigation of noise sources in high-speed jets via correlation measurements , 2005, Journal of Fluid Mechanics.

[14]  A. Schröder,et al.  3D3C-coherent structure measurements in a free turbulent jet , 2010 .

[15]  F. Scarano.  Iterative image deformation methods in PIV , 2002 .