Broaband Noise Prediction Models And Measurements of Tip Leakage Flows

Grilliat, Julien; Jondeau, Emmanuel; Jacob, Marc C.; Roger, Michel; Camussi, Roberto

doi:10.2514/6.2008-2845

Cited by 14 publications

(21 citation statements)

References 8 publications

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“…The radiated sound measurements of that configuration are compared to a prediction using Amiet's theory based on the geometrical and flow information provided therein. Figure 6 compares the unsteady surface pressure measured from Grilliat et al (2008) to the surface pressure prediction from Eq. (10).…”

Section: A Comparison Of Predictive Methodology With Single Airfoil mentioning

confidence: 99%

“…As a test of the predictive capability of the present method, a comparison is made from a previously published test case in the literature (Grilliat et al, 2008). Comparison is made of the unsteady surface pressure measured therein to that of the delta wing surface pressure.…”

Section: A Comparison Of Predictive Methodology With Single Airfoil mentioning

confidence: 99%

“…(10). The surface pressure was measured near the tip at the trailing edge, and the prediction is made using the correlations with U o , c and a given from Grilliat et al (2008) as 70 m/s, 0.2 m, and 15 with a tip gap of 5% of the span. The overall trend of the measured spectrum is well reproduced by the prediction.…”

Section: A Comparison Of Predictive Methodology With Single Airfoil mentioning

confidence: 99%

“…Many successful studies of tip vortex noise have been performed in the inertial frame as it allows for the easiest reduction of competing noise sources (Brooks and Marcolini, 1986;Brooks et al, 1989;Grilliat et al, 2007;Grilliat et al, 2008;Jacob et al, 2010). In each of these cases, it was found to have a comparatively weak contribution to the overall spectrum.…”

Section: Introductionmentioning

confidence: 96%

“…This is accomplished using the trailing edge noise theory proposed by Amiet (1976) combined with empirical data as inputs to the formulation. The theory is evaluated in comparison to a relatively simple test case of a single airfoil with a tip gap obtained from the literature (Grilliat et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Measurement and analysis of radiated sound from a low speed fan with a large tip gap

Bilka

Anthoine

Schram

2014

The Journal of the Acoustical Society of America

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The wake flow field and radiated sound from a low speed axial fan is studied experimentally. The fan geometry uses controlled diffusion blades and is designed with a low aspect ratio (0.9). The fan is installed with a large tip gap, approximately 10% of the blade span. The radiated sound field is analyzed using a known trailing edge noise formulation. First, the model is compared to an experiment of a single airfoil in a wind tunnel to assess the predictive capabilities. Second, measurements of the fan are made at two different blade loading conditions. Hot wire measurements are made in the near wake of the fan to assess the extent of the tip leakage flow for each condition. The radiated sound fields are compared with the trailing edge noise theory. Use is made of the wake measurements as an input to a surface pressure model. When the fan is operated with the optimal blade loading, the influence of the tip leakage flow is found to be of secondary acoustic impact. When the fan is operated at a high loading condition for the blades, a more significant leakage flow develops and is found to be responsible for the dominant radiated sound.

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Section: A Comparison Of Predictive Methodology With Single Airfoil mentioning

confidence: 99%

Section: A Comparison Of Predictive Methodology With Single Airfoil mentioning

confidence: 99%

Section: A Comparison Of Predictive Methodology With Single Airfoil mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Measurement and analysis of radiated sound from a low speed fan with a large tip gap

Bilka

Anthoine

Schram

2014

The Journal of the Acoustical Society of America

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Experimental study of a tip leakage flow: wavelet analysis of pressure fluctuations

et al. 2010

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A wavelet-based conditional analysis of unsteady flow and sound signals highlights\ud the role of intermittent perturbations both in the sound generation and the unsteady\ud field of an aerofoil tip leakage flow experiment. It is shown how the most probable\ud flow perturbations generated at the pressure side tip edge are convected through\ud the gap and swept downstream along the suction side past the trailing edge tip\ud corner, where they radiate sound. The nascent sound sources are identified and\ud localized in the clearance between 40% and 60% of the chord. It is also found\ud that the time dependence of the averaged intermittent structures scales with the\ud inverse of the square root of the mean velocity and a physical interpretation based\ud on a simple potential vortex model is proposed. The data are retrieved from an\ud experiment that has been carried out at low Mach number (Ma<0.3) in an anechoic\ud test facility. A single motionless instrumented NACA 5510 aerofoil was mounted into\ud the potential core of an open rectangular jet between two plates with an adjustable\ud clearance. The tip leakage flow was ensured by the 5% camber and a 15◦ angle\ud of attack. A large database obtained by a variety of measurement techniques is\ud thus available for the present analysis. More specifically, the conditional approach\ud is applied to joint far field, wall pressure and particle image velocimetry (PIV)\ud measurements. The wall pressure probes are located along the suction side tip edge\ud and on the tip inside the gap, whereas the PIV plane is parallel to the mid-gap\ud plane. Additional joint wall pressure and single hot-wire anemometry (HWA)\ud measurements are also analysed with a hot-wire probe located near the trailing edge tip\ud corner. The conditional averaging is triggered by high-energy wavelet events selected\ud in a reference signal by setting a threshold to the so-called local intermittency measure

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Aeroacoustic Investigation of a Single Airfoil Tip Leakage Flow

Jacob

Grilliat

Camussi³

et al. 2010

International Journal of Aeroacoustics

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Combined near and far field aeroacoustic measurements have been carried out during an original laboratory scale low Mach number (0-0.3) experiment about the tip leakage flow past a single non-rotating airfoil. Such measurements were made possible by the use of a single airfoil located in the potential core of an open jet flow in the anechoic wind tunnel of the Ecole Centrale de Lyon. The airfoil was mounted between two flat plates. A strong tip clearance flow was achieved without rotation by paying a special attention to the choice of the airfoil which was a 5% camber, 10% thickness NACA5510 airfoil that provided a high lift at a 15°angle of attack. The experiment gave rise to an extensive data set obtained with several flow velocity measurement techniques (HWA, LDA, PIV), steady and unsteady pressure measurements on the airfoil and the casing plate as well as far field pressure measurements. Further, cross-analyses of various velocity and pressure signals allowed to locating sources and identifying their mechanisms. Results showed evidence of two components of tip leakage broadband self noise.

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Broaband Noise Prediction Models And Measurements of Tip Leakage Flows

Cited by 14 publications

References 8 publications

Measurement and analysis of radiated sound from a low speed fan with a large tip gap

Measurement and analysis of radiated sound from a low speed fan with a large tip gap

Experimental study of a tip leakage flow: wavelet analysis of pressure fluctuations

Aeroacoustic Investigation of a Single Airfoil Tip Leakage Flow

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