VOLUME

747

Journal

of  Fluid

Mechanics

25  May201425  May2014

VOLUME

747

Journal

of  Fluid

Mechanics

25  May  201425  May  2014

VOLUME  747VOLUME  747

74774725  May  201425  May  2014

Experimental Investigation of Trailing Edge Aeroacoustics

Along with stricter noise regulations in the air transportation and wind energy sectors comes the need to improve our understanding of aeroacoustic noise generation and sources. Engineers face new challenges in the attenuation of noise sources located on lifting surfaces, a prominent example being trailing edge noise. The combination of state of the art high-speed Particle Image Velocimetry (PIV) and phased array acoustic measurements opens new possibilities for the investigation of the underlying processes sustaining noise generation and is the focus of our research.

S. Pröbsting, F. Scarano, S. Pirozzoli, M. Bernardini (2013) “On the estimation of wall pressure coherence using time-resolved tomographic PIV”, Experiments in Fluids S. Pröbsting, J. Serpieri, F. Scarano (2014) “Amplitude modulation of instabilities generating aerofoil tonal noise”, Journal of Fluid Mechanics S. Pröbsting, F. Scarano, S. Pirozzoli, M. Bernardini (2012) “A comparative study of turbulent boundary layer wall pressure fluctuations obtained from high-speed tomo- PIV and DNS”, 16th Int Symp on Appl of Laser Tech to Fluid Mech. S. Pröbsting, J. Serpieri, F. Scarano (2013) “Investigation of tonal noise generation on an airfoil with time-resolved PIV”, 19th AIAA/CEAS Aeroacoustics Conference S. Pröbsting, J. Serpieri, F. Scarano (2013) “High-speed PIV analysis of trailing edge aeroacoustics”, 10th International Symposium on Particle Image Velocimetry S. Pröbsting, F. Scarano (2014) “Experimental investigation of isolated aerofoil noise”, 21st Intenatioanl Congress of Sound and Vibrations F. Scarano, S. Ghaemi, S. Pröbsting (2013) “Data reduction from time-resolved tomographic PIV for unsteady pressure evaluation”, 51st AIAA Aerospace Sciences Meeting M. Tuinstra, S.Pröbsting, F. Scarano (2013) “On the use of particle image velocimetry to predict trailing edge noise”, 19th AIAA/CEAS Aeroacoustics Conference

PhD Candidate: Stefan Pröbsting Department: AWEP Section: Aerodynamics Supervisor: F. Scarano Promoter: F. Scarano Start date: 01-8-2011 Funding: AFDAR Cooperations: NLR, VKI, Univ. Notre Dame Type: Scientific

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Tonal noise generated by many airfoil profiles at low to moderate Reynolds numbers is related to laminar boundary layer instabilities and a feedback between the noise source at the trailing edge and the region of receptivity of the boundary layer. In the past this phenomenon has been investigated, but ambiguities due to the limited information on the aeroacoustic source remained. State of the art high-speed PIV techniques available at TU Delft in combination with acoustic measurements provide a more complete picture of the noise generation process. Time-resolved PIV allows for spectral analysis of the relevant aeroacoustic quantities within the source region. With this unique set-up it was now possible to relate the occurrence of multiple, discrete tones to a quasi-periodic amplitude modulation of boundary layer instabilities passing the trailing edge. This work provides a good example for the potential of high-speed PIV systems in the invest igat ion of aeroacoust ic source mechanisms. Other areas of our research include the deduction and measurement of relevant parameters for trailing edge noise based on advanced PIV techniques, such as time-resolved and volumetric tomographic PIV measurements.

Set-up of high-speed PIV experiment for trailing edge noise study in TU Delft V-Tunnel Cover page of Journal of Fluid Mechanics, May 2014

Turbulent boundary layer passing a trailing edge Volumetric and time-resolved tomographic PIV