On the aeroacoustic tonal noise generation mechanism of a sharp-edged. plate

Size: px
Start display at page:

Download "On the aeroacoustic tonal noise generation mechanism of a sharp-edged. plate"

Transcription

1 On the aeroacoustic tonal noise generation mechanism of a sharp-edged plate Danielle J. Moreau, Laura A. Brooks and Con J. Doolan School of Mechanical Engineering, The University of Adelaide, South Australia, Australia 5005 danielle.moreau@adelaide.edu.au, laura.brooks@adelaide.edu.au, con.doolan@adelaide.edu.au 1

2 Abstract This letter presents an experimental study on the tonal noise generated by a sharp-edged flat plate at low-to-moderate Reynolds number. Flow and far-field noise data reveal that, in this particular case, the tonal noise appears to be governed by vortex shedding processes. Also related to the existence of the tonal noise is a region of separated flow slightly upstream of the trailing edge. Hydrodynamic fluctuations at selected vortex shedding frequencies are strongly amplified by the inflectional mean velocity profile in the separated shear layer. The amplified hydrodynamic fluctuations are diffracted by the trailing edge, producing strong tonal noise. c 2010 Acoustical Society of America PACS: Ra 2

3 1. Introduction The noise radiated from airfoils operating at low-to-moderate Reynolds number ( Re c , based on chord) may contain one or more high amplitude tonal components. While airfoil tonal noise has been the subject of many investigations over the years, there is no general consensus on the tonal noise generation mechanism. Furthermore, no experimental studies have conclusively verified any of the proposed hypotheses. The first known experimental study on airfoil tonal noise was conducted by Paterson et al. 1. Using the cross-correlation of boundary layer and far-field acoustic data, they concluded that airfoil tonal noise is governed by vortex shedding from the trailing edge. Tam 2 disagreed with this hypothesis and proposed that tonal noise is produced by an aeroacoustic feedback loop between the first point of boundary layer instability and a point in the wake which acts as the noise source. The acoustic waves emitted by the noise source travel upstream to enhance the hydrodynamic instabilities at their origin. Tam 2 and most subsequent researchers 3 8 have assumed that laminar boundary layer instabilities, known as Tollmien-Schlichting (T-S) waves, are responsible for the discrete frequency noise. The aeroacoustic feedback loop proposed by Tam 2 has since been modified by a number of researchers 3 5,9,10, who have suggested that airfoil tonal noise is produced by a feedback loop between instabilities in the laminar boundary layer and acoustic waves generated at the trailing edge. They suggest that the boundary-layer instabilities are diffracted at the trailing edge to produce acoustic waves that travel upstream and reinforce the hydrodynamic instabilities at their source. More recently, Nash et al. 6 and McAlpine et al. 7 stated that the feedback process is not a necessary condition for the generation of acoustic tones. They proposed that airfoil tonal noise is generated by the trailing edge diffrac- 3

4 tion of boundary layer T-S waves that are strongly amplified by the inflectional mean velocity profile in the separated shear layer at the trailing edge. Through analysis of experimental results, this letter presents a mechanism for the production of tonal noise based on vortex shedding processes at the trailing edge. 2. Experimental method Experiments were performed in the anechoic wind tunnel at the University of Adelaide. This facility contains a 75 mm x 275 mm test section with a free-stream turbulence intensity of 0.3%. The flat plate model used in this study has a chord of 200 mm, a span of 450 mm and a thickness of 5 mm. The flat plate leading edge is elliptical with semi-major axis of 8 mm and semi-minor axis of 2.5 mm while the trailing edge of the top surface is a wedge shape which forms a 12 angle with the lower flat surface of the plate as shown in Fig. 1 (a). The acoustic measurements were recorded using two B&K 1/2 microphones (Model No. 4190): one 585 mm directly above and one 585 mm directly below the trailing edge. As it is likely that the far-field noise measurements are contaminated by other noise sources such as background noise, the method for extracting and analysing trailing edge noise developed by Moreau et al. 11 has been used to process the far-field noise measurements. However, as the tonal noise levels are much higher than the background noise levels, the effect of the correction was seen to be negligible. Hot-wire anemometry was used to measure both unsteady velocity data in the streamwise direction, and the boundary layer profile at the trailing edge. A TSI T1.5 single wire probe with a wire length of 1.27 mm and a wire diameter of 3.81 µm was used. The probe was positioned using a Dantec automatic traverse which allowed continuous movement in the streamwise (x), vertical (y) and spanwise (z) directions. The origin of the co-ordinate system is located at the centre of the trailing edge. Both 4

5 the far-field noise measurements and the velocity data were collected using a National Instruments board at a sampling frequency of 2 15 Hz for a sample time of 8 s. Experiments were conducted with the flat plate positioned at zero angle of attack at free-stream velocities between U = 5 and 15 m/s, corresponding to Reynolds numbers of Re c Experimental results and discussion The far-field acoustic spectra for the flat plate at U = 15 m/s is compared with background noise spectra in Fig. 1 (b). The background noise was measured with the top trailing edge microphone. The far-field noise spectrum is composed of a broadband contribution centered around the peak tone and a number of discrete equi spaced tones. The value of the difference between two consecutive discrete frequencies is f 244 Hz. The tones observed in the far-field noise spectra are the 2nd 5th harmonics: f 2 = 480 Hz; f 3 = 729; f 4 = 960 Hz and f 5 = 1212 Hz, of the fundamental with frequency f 1 = 244 Hz. The frequencies of the dominant tones radiated by the flat plate as a function of free-stream velocity are shown in Fig. 1 (c). In this figure, a major tone refers to a tone that is clearly visible but lower in amplitude than the peak tone. At flow speeds between U = 8 and 15 m/s, multiple tones are produced by the flat plate. Below U = 8 m/s, only a single tone is visible in the far-field noise spectra. The tonal frequencies in Fig. 1 (c) display a clear ladder-type structure consistent with the results of previous researchers 1,5,6. Paterson et al. 1 found that the frequencies of the discrete tones radiated by airfoils at low angles of attack displayed a dependence on the U 0.8 power law and that the frequency scaling law of U 1.5 described the relationship between the average behaviour of the tonal noise and the free-stream velocity. These scaling laws for an airfoil do 5

6 not describe the ladder structure of the flat plate tonal noise frequencies in Fig. 1 (c). Instead, the frequencies of the flat plate tones are seen to scale with free-stream velocity according to U The discrepancy in the frequency scaling law is attributed to significant differences in the geometry of the NACA 0012 and NACA 0018 airfoils used by Paterson et al. 1 and the flat plate studied here. Fig. 1 (d) shows the amplitude of the peak tonal component as a function of freestream velocity. At very low flow speeds, the amplitude of the peak tone increases with an increase in flow velocity. The intensity of the peak tone reaches a maximum at U = 12 m/s, before decreasing with a further increase in flow speed and becoming undetectable at U = 16 m/s. This trend is again consistent with the findings of others 1,5 suggesting that although the geometry differs, the mechanism studied here is the same as that investigated by previous researchers. To gain further insight into the tonal noise generation mechanism, simultaneous flow and velocity data were measured at the free-stream velocity of U = 15 m/s. Fig. 2 shows spectral maps of the fluctuating velocity measured in the streamwise direction below the lower flat surface of the plate at y/c = High intensity velocity fluctuations are visible at the far-field tonal noise frequencies, f 2 to f 5, both upstream and downstream of the trailing edge. In the wake, an additional high energy peak is observed at the fundamental frequency of f 1 = 244 Hz (see Fig. 2 (b)). This fundamental tone is not observed in either the flow field upstream of the trailing edge or in the far-field noise spectra. The high intensity velocity fluctuations in the wake at the fundamental frequency, f 1, and at the far-field tonal noise frequencies, f 2 to f 5, are attributed to vortex shedding from the trailing edge. Upstream of the trailing edge, the high intensity fluctuations at the tonal noise frequencies, f 2 to f 5, are dominated by acoustic disturbances, as discussed later. Recent studies 6,7 have highlighted the importance of flow separation upstream of 6

7 the trailing edge in the generation of acoustic tones. The inflectional mean velocity profile in the separated laminar shear layer acts as a tonal selection and amplification mechanism. Many experimental studies on airfoil tonal noise have measured a region of flow separation on the airfoil laminar flow surface upstream of the trailing edge using a variety of techniques including laser velocimetry, hot-wire anemometry and flow visualization 6, While concerns have been raised over the possible influence of hot-wire measurement techniques on the flow in the vicinity of the separation region 6,7, a comparative study by Brendel and Mueller 13 demonstrated that hot-wire anemometry was as accurate as laser velocimetry in the detection of flow separation. This is on the proviso that the probe is positioned at an angle of less than 10 to the horizontal, as was done here. In this work, the hot-wire probe was kept outside of the separation bubble at all times. Examination of the mean velocity underneath the plate (Fig. 3 (a)) clearly shows a small region of flow separation is located upstream of the trailing edge, very close to the surface of the plate. The velocity is observed to accelerate as it approaches the trailing edge, reach a peak and decelerate, consistent with flow outside of a separation bubble. Only tones at harmonics of the vortex shedding frequency, f 2 to f 5, are visible upstream of the trailing edge and in the far-field noise spectrum suggesting that velocity fluctuations at these frequencies are strongly amplified by the inflectional mean velocity profile in the shear layer associated with the separation bubble as per the mechanism discussed by Nash et al. 6 and McAlpine et al. 7. High amplitude tonal sound is produced as these amplified hydrodynamic fluctuations are diffracted by the trailing edge 16. No high amplitude tone is observed in the far-field noise spectra at the fundamental, f 1, as fluctuations at this frequency are not amplified by the inflectional mean velocity profile in the shear layer. Most previous researchers 2 7 have assumed that T-S waves are responsible for 7

8 the tonal noise components. For the case of a laminar flat plate boundary layer, the frequencies of unstable disturbances are restricted to the region within the neutral stability curve for Blasius flow. The boundary layer profile was measured below the trailing edge of the flat plate and was found to have a Blasius velocity profile above the small region of flow separation. This indicates that the flow is therefore laminar through the boundary layer on the lower flat surface of the plate upstream of the separation bubble. Fig. 3 (b) shows the neutral stability curve for Blasius flow 12. In this figure, ω is the angular frequency, ν is the kinematic viscosity and Re δ is the Reynolds number based on boundary layer displacement thickness at the trailing edge. The boundary layer displacement thickness was measured to be δ = mm at the trailing edge. The tonal noise frequencies, f 2 to f 5, all lie outside the region of instability, showing that T-S waves should not exist at these frequencies in the laminar boundary layer upstream of the separation bubble. While the fundamental frequency, f 1, does lie within the bounds of the instability region, high intensity velocity fluctuations are not observed at this frequency upstream of the trailing edge. In Fig. 2 (a), an additional high energy peak is visible in the laminar boundary layer upstream of the separation bubble at a frequency of 140 Hz. This high energy peak is believed to be a T-S wave as its frequency sits within the region of instability, as shown in Fig. 3 (b). The frequencies of the tonal noise components in the far-field noise spectra do not correspond to that of the T-S wave indicating that T-S waves are not involved in the tonal noise production process. Fig. 4 shows the coherence and phase difference between the fluctuating velocity measured in the streamwise direction and the far-field acoustic noise at the peak tonal frequency of f 3 = 729 Hz. Phase and coherence measurements at the other far-field tonal noise frequencies, f 2, f 4 and f 5, follow the same trend as those for f 3. Fig. 4 (a) shows that the coherence between the far-field acoustic and velocity 8

9 signals is at a maximum when the hot-wire is located close to the trailing edge. The coherence plot displays a clear minimum at x/c = 0.1, with the coherence falling to 0.1 at this position. This is observed in the velocity spectra in Fig. 2 (b) as a significant decrease in the amplitude of the velocity fluctuations of f 3 at the point of minimum coherence. Locating the hot-wire at this position has likely disturbed the vortex formation process, resulting in lower amplitude velocity fluctuations at this frequency and thus lower coherence. As the hot-wire moves downstream of x/c = 0.1, the velocity fluctuations at f 3 regain their amplitude as the vortex has formed and continues downstream and the coherence is observed to increase. Far upstream and downstream of the trailing edge the velocity fluctuations at f 3 become almost undetectable and thus low coherence levels are observed at these locations. The spanwise coherence was measured in the very near wake of the trailing edge and showed that highly coherent spanwise vortical structures were present. Even if a vortex is disturbed at its point of formation in the wake by the hot-wire probe or the probe holder, the strong spanwise vortical structures will induce similar fluid mechanics about the plate trailing edge as evidenced by the velocity profile in Fig. 3 (a). Fig. 4 (b) shows that when the hot-wire is located upstream of the separation bubble, the phase difference between the fluctuating velocity and far-field acoustic signals at the peak tonal frequency of f 3 = 729 Hz is nearly constant. This indicates that the acoustic component of velocity is dominant there. The high amplitude velocity fluctuations at the far-field tonal frequencies, f 2 to f 5, measured upstream of separation in Fig. 2 (a) are therefore acoustic disturbances. Acoustic waves are produced at the trailing edge at the selected vortex shedding frequencies of f 2 to f 5 and these acoustic waves are radiated upstream along the lower flat surface of the plate. Both Paterson et al. 1 and Sunyach et al. 17 also detected acoustic waves traveling 9

10 upstream from the trailing edge inside the boundary layer in their experiments on airfoils in low Reynolds number flow. Downstream of the trailing edge, the phase difference between the fluctuating velocity and far-field acoustic signals varies linearly (see Fig. 4 (b)) indicating the development of strong hydrodynamic fluctuations. It is worth noting, that the authors used similar analysis to that of Tam 2 to investigate the possibility of an aeroacoustic feedback loop between the hydrodynamic fluctuations and the acoustic waves generated at the trailing edge or at a point in the wake. Tam 2 derived equations describing the total phase change around the aeroacoustic loop. In the present study, no aeroacoustic feedback loop was identified that agreed with the phase and coherence information of Fig. 4 or with other experimental observations. The results presented here instead agree with the findings of Nash et al. 6 and McAlpine et al. 7 who suggest that the feedback process is not a necessary condition for the generation of acoustic tones. Recently, Jones et al. 10 identified a feedback mechanism that involves the generation of boundary layer disturbances at the leading edge through acoustic excitation from the trailing edge. This feedback loop was shown to exist only in certain flow conditions 18. It is possible that the present results are an example of flow conditions where the loop cannot be supported. More work is required to experimentally confirm if the new loop proposed by Jones et al. 10 can explain these and previously reported results. 4. Conclusion This paper has presented results of an experimental investigation on the tonal noise generated by a sharp-edged flat plate at low-to-moderate Reynolds number. Experimental results have indicated that in this particular case, the tonal noise generation mechanism appears to be governed by vortex shedding processes at the trailing edge. Velocity fluctuations at the selected vortex shedding harmonics are strongly 10

11 amplified by the inflectional mean velocity profile in the separated shear layer on the plate laminar flow surface. High amplitude tonal sound is produced when the amplified hydrodynamic fluctuations are diffracted by the trailing edge. Acknowledgments This work has been supported by the Australian Research Council under grant DP The mechanics of quiet airfoils. References and links 1 R. Paterson, P. Vogt, and M. Fink, Vortex noise of isolated airfoils, J. Aircraft 10(5), (1973). 2 C. Tam, Discrete tones of isolated airfoils, J. Acoust. Soc. Am. 55(6), (1974). 3 M. Fink, Prediction of airfoil tone frequencies, J. Aircraft 12(2), (1975). 4 R. Longhouse, Vortex shedding noise of low tip speed, axial flow fans, J. Sound Vib. 53, (1977). 5 H. Arbey and J. Bataille, Noise generated by airfoil profiles placed in a uniform laminar flow, J. Fluid Mech. 134, (1983). 6 E. Nash, M. Lowson, and A. McAlpine, Boundary-layer instability noise on airfoils, J. Fluid Mech. 382, (1999). 7 A. McAlpine, E. Nash, and M. Lowson, On the generation of discrete frequency tones by the flow around an airfoil, J. Sound Vib. 222(5), (1999). 8 M. Kingan and J. Pearse, Laminar boundary layer instability noise produced by an aerofoil, J. Sound Vib. 322, (2009). 9 S. Wright, The acoustic spectrum of axial flow machines, J. Sound Vib. 45, (1976). 11

12 10 L. Jones, R. Sandberg, and N. Sandham, Stability and receptivity characteristics of a laminar separation bubble on an aerofoil, J. Fluid Mech. 648, (2010). 11 D. Moreau, M. Tetlow, L. Brooks, and C. Doolan, Acoustic analysis of flat plate trailing edge noise, in 20th International Congress on Acoustics, ICA 2010 (2010). 12 C. Lin, Theory of hydrodynamic stability (Cambridge University Press, Great Britain) (1955). 13 M. Brendel and T. J. Mueller, Boundary-layer measurements on an airfoil at low Reynolds numbers, J. Aircraft 25, (1988). 14 S. Yarusevych, J. Kawall, and P. Sullivan, Unsteady separated flow characterisation on airfoils using time-resolved surface pressure measurements, AIAA J. 46(2), (2008). 15 S. Makiya, A. Inasawa, and M. Asai, Vortex shedding noise and noise radiation from a slat trailing edge, AIAA J. 48(2), (2010). 16 J. Ffowcs Williams and L. Hall, Aerodynamic sound generation by turbulent flow in the vicinity of a scattering half plane, J. Fluid Mech. 40, (1970). 17 M. Sunyach, H. Arbey, D. Robert, J. Bataille, and G. Comte-Bellot, Correlations between far field acoustic pressure and flow characteristics for a single airfoil, in AGARD Conference No. 131, Noise Mechanisms, Paper No. 5 (1973). 18 L. Jones and R. Sandberg, Numerical investigation of tonal airfoil self-noise generated by an acoustic feedback-loop, in 16th AIAA/CEAS Aeroacoustics Conference (2010). 12

13 List of Figures Fig. 1 Flat plate geometry and corresponding far-field acoustic data: (a) flat plate geometry, (b) far-field acoustic spectra compared to background noise spectra for U = 15 m/s, (c) tonal frequency relationship and (d) amplitude of the peak tonal component. (Color online) Fig. 2 Spectral maps of the fluctuating velocity, U, measured in the streamwise direction at y/c = for U = 15 m/s: (a) upstream, and (b) downstream of the trailing edge. (Color online) Fig. 3 (a) The mean velocity measured in the streamwise direction at y/c = for U = 15 m/s and (b) the curve of neutral stability for Blasius flow 12. (Color online) Fig. 4 (a) Coherence and (b) phase difference between the fluctuating velocity measured in the streamwise direction at y/c = and the farfield acoustic noise at f 3 = 729 Hz for U = 15 m/s. (Color online)

14 (a) LE 12 TE Fig. 1. Fig

15 Fig. 3. Fig

Empirical study of the tonal noise radiated by a sharpedged flat plate at low-to-moderate Reynolds number

Empirical study of the tonal noise radiated by a sharpedged flat plate at low-to-moderate Reynolds number Paper Number 44, Proceedings of ACOUSTICS 2011 Empirical study of the tonal noise radiated by a sharpedged flat plate at low-to-moderate Reynolds number Danielle J. Moreau, Laura A. Brooks and Con J. Doolan

More information

Acoustic analysis of flat plate trailing edge noise

Acoustic analysis of flat plate trailing edge noise Proceedings of 20th International Congress on Acoustics, ICA 2010 23 27 August 2010, Sydney, Australia PACS: 43.28.Ra ABSTRACT Acoustic analysis of flat plate trailing edge noise D.J. Moreau, M.R. Tetlow,

More information

INFLUENCE OF ACOUSTIC EXCITATION ON AIRFOIL PERFORMANCE AT LOW REYNOLDS NUMBERS

INFLUENCE OF ACOUSTIC EXCITATION ON AIRFOIL PERFORMANCE AT LOW REYNOLDS NUMBERS ICAS 2002 CONGRESS INFLUENCE OF ACOUSTIC EXCITATION ON AIRFOIL PERFORMANCE AT LOW REYNOLDS NUMBERS S. Yarusevych*, J.G. Kawall** and P. Sullivan* *Department of Mechanical and Industrial Engineering, University

More information

On the noise reduction mechanism of a flat plate serrated trailing edge at low-to-moderate Reynolds number

On the noise reduction mechanism of a flat plate serrated trailing edge at low-to-moderate Reynolds number On the noise reduction mechanism of a flat plate serrated trailing edge at low-to-moderate Reynolds number Danielle J. Moreau, Laura A. Brooks and Con J. Doolan The University of Adelaide, South Australia,

More information

Numerical study of low Reynolds number airfoil flows

Numerical study of low Reynolds number airfoil flows Proceedings of the Acoustics 212 Nantes Conference 23-27 April 212, Nantes, France Numerical study of low Reynolds number airfoil flows O. Marsden and T. Charrel Laboratoire de Mecanique des Fluides et

More information

An experimental study of airfoil instability tonal noise with trailing edge serrations

An experimental study of airfoil instability tonal noise with trailing edge serrations An experimental study of airfoil instability tonal noise with trailing edge serrations Tze Pei Chong a, *, Phillip Joseph b a School of Engineering and Design, Brunel University, Uxbridge, UB8 3PH,UK b

More information

Numerical and Experimental Investigation of the Flow-Induced Noise of a Wall Mounted Airfoil

Numerical and Experimental Investigation of the Flow-Induced Noise of a Wall Mounted Airfoil Numerical and Experimental Investigation of the Flow-Induced Noise of a Wall Mounted Airfoil Paul Croaker, Danielle Moreau, Manuj Awasthi, Mahmoud Karimi, Con Doolan, Nicole Kessissoglou School of Mechanical

More information

AEROACOUSTIC INVESTIGATION OF THE EFFECT OF A DETACHED FLAT PLATE ON THE NOISE FROM A SQUARE CYLINDER

AEROACOUSTIC INVESTIGATION OF THE EFFECT OF A DETACHED FLAT PLATE ON THE NOISE FROM A SQUARE CYLINDER Abstract AEROACOUSTIC INVESTIGATION OF THE EFFECT OF A DETACHED FLAT PLATE ON THE NOISE FROM A SQUARE CYLINDER Aniket D. Jagtap 1, Ric Porteous 1, Akhilesh Mimani 1 and Con Doolan 2 1 School of Mechanical

More information

Aerodynamic noise produced in flow around an automobile bonnet

Aerodynamic noise produced in flow around an automobile bonnet Aerodynamic noise produced in flow around an automobile bonnet Hiroshi Yokoyama 1, Takahiro Nakajima 2, Taishi Shinohara 3, Masashi Miyazawa 4 and Akiyoshi Iida 5 1,2,3,5 Department of Mechanical Engineering,

More information

PUBLISHED VERSION. Published version: https://www.acoustics.asn.au/conference_proceedings/aasnz2016/abstracts/themespapers.htm#p39

PUBLISHED VERSION. Published version: https://www.acoustics.asn.au/conference_proceedings/aasnz2016/abstracts/themespapers.htm#p39 PUBLISHED VERSION Jesse Coombs, Con Doolan, Anthony Zander, Danielle Moreau and Laura Brooks Statistical estimation of trailing edge noise from finite wall-mounted airfoils Proceedings of the Acoustics2016

More information

Self noise produced by an airfoil with non-flat plate trailing edge serrations

Self noise produced by an airfoil with non-flat plate trailing edge serrations Self noise produced by an airfoil with non-flat plate trailing edge serrations Tze Pei. Chong 1 and Alexandros Vathylakis 2 School of Engineering and Design, Brunel University, Uxbridge, UB8 3PH, United

More information

On vortex shedding from an airfoil in low-reynolds-number flows

On vortex shedding from an airfoil in low-reynolds-number flows J. Fluid Mech. (2009), vol. 632, pp. 245 271. c 2009 Cambridge University Press doi:10.1017/s0022112009007058 Printed in the United Kingdom 245 On vortex shedding from an airfoil in low-reynolds-number

More information

Self-noise prediction of a sharp-edged strut using a quasi-periodic CFD-BEM technique

Self-noise prediction of a sharp-edged strut using a quasi-periodic CFD-BEM technique Self-noise prediction of a sharp-edged strut using a quasi-periodic CFD-BEM technique Mahmoud Karimi 1 ; Paul Croaker 1 ; Nicole Kessissoglou 1 ; Con Doolan 2 ; Steffen Marburg 3 1 School of Mechanical

More information

EXCITATION OF GÖRTLER-INSTABILITY MODES IN CONCAVE-WALL BOUNDARY LAYER BY LONGITUDINAL FREESTREAM VORTICES

EXCITATION OF GÖRTLER-INSTABILITY MODES IN CONCAVE-WALL BOUNDARY LAYER BY LONGITUDINAL FREESTREAM VORTICES ICMAR 2014 EXCITATION OF GÖRTLER-INSTABILITY MODES IN CONCAVE-WALL BOUNDARY LAYER BY LONGITUDINAL FREESTREAM VORTICES Introduction A.V. Ivanov, Y.S. Kachanov, D.A. Mischenko Khristianovich Institute of

More information

DIRECT SIMULATION OF TRAILING-EDGE NOISE GENERATED BY A CONTROLLED DIFFUSION AIRFOIL USING A LATTICE-BOLTZMANN METHOD

DIRECT SIMULATION OF TRAILING-EDGE NOISE GENERATED BY A CONTROLLED DIFFUSION AIRFOIL USING A LATTICE-BOLTZMANN METHOD DIRECT SIMULATION OF TRAILING-EDGE NOISE GENERATED BY A CONTROLLED DIFFUSION AIRFOIL USING A LATTICE-BOLTZMANN METHOD M. Sanjosé, S. Moreau Department of Mechanical Engineering Université de Sherbrooke

More information

Prediction of noise from a wing-in-junction flow using computational fluid dynamics

Prediction of noise from a wing-in-junction flow using computational fluid dynamics Proceedings of Acoustics - Fremantle -3 November, Fremantle, Australia Prediction of noise from a wing-in-junction flow using computational fluid dynamics Con J. Doolan, Jesse L. Coombs, Danielle J. Moreau,

More information

Validation of unstructured-mesh LES of the trailing-edge flow and noise of a Controlled-Diffusion airfoil

Validation of unstructured-mesh LES of the trailing-edge flow and noise of a Controlled-Diffusion airfoil Center for Turbulence Research Proceedings of the Summer Program 006 1 Validation of unstructured-mesh LES of the trailing-edge flow and noise of a Controlled-Diffusion airfoil By S. Moreau, D. Neal, Y.

More information

Proceedings of Meetings on Acoustics

Proceedings of Meetings on Acoustics Proceedings of Meetings on Acoustics Volume 19, 2013 http://acousticalsociety.org/ ICA 2013 Montreal Montreal, Canada 2-7 June 2013 Noise Session 3aNSb: Aviaton, Aviation Engines, and Flow Noise 3aNSb3.

More information

Effect of Airfoil Aerodynamic Loading on Trailing-Edge Noise Sources

Effect of Airfoil Aerodynamic Loading on Trailing-Edge Noise Sources AIAA JOURNAL Vol. 43, No. 1, January 2005 Effect of Airfoil Aerodynamic Loading on Trailing-Edge Noise Sources Stéphane Moreau Valeo Motors and Actuators, 78321 La Verrière, France and Michel Roger Ecole

More information

THE ROLE OF LOCALIZED ROUGHNESS ON THE LAMINAR-TURBULENT TRANSITION ON THE OBLIQUE WING

THE ROLE OF LOCALIZED ROUGHNESS ON THE LAMINAR-TURBULENT TRANSITION ON THE OBLIQUE WING THE ROLE OF LOCALIZED ROUGHNESS ON THE LAMINAR-TURBULENT TRANSITION ON THE OBLIQUE WING S.N. Tolkachev*, V.N. Gorev*, V.V. Kozlov* *Khristianovich Institute of Theoretical and Applied Mechanics SB RAS

More information

Experimental analysis of the radiated noise from a small propeller

Experimental analysis of the radiated noise from a small propeller Proceedings of th International Congress on Acoustics, ICA 10 23-27 August 10, Sydney, Australia Experimental analysis of the radiated noise from a small propeller Angus Leslie, K C Wong, Doug Auld The

More information

EXPERIMENTS OF CLOSED-LOOP FLOW CONTROL FOR LAMINAR BOUNDARY LAYERS

EXPERIMENTS OF CLOSED-LOOP FLOW CONTROL FOR LAMINAR BOUNDARY LAYERS Fourth International Symposium on Physics of Fluids (ISPF4) International Journal of Modern Physics: Conference Series Vol. 19 (212) 242 249 World Scientific Publishing Company DOI: 1.1142/S211945128811

More information

Noise modelling of wing-in-junction flows

Noise modelling of wing-in-junction flows Proceedings of Acoustics 013 Victor Harbor 17-0 November 013, Victor Harbor, Australia Noise modelling of wing-in-junction flows J.L. Coombs (1), C.J. Doolan (1), D.J. Moreau (1), A.C. Zander (1) and L.A.

More information

International Conference on Methods of Aerophysical Research, ICMAR 2008

International Conference on Methods of Aerophysical Research, ICMAR 2008 International Conference on Methods of Aerophysical Research, ICMAR 8 EXPERIMENTAL STUDY OF UNSTEADY EFFECTS IN SHOCK WAVE / TURBULENT BOUNDARY LAYER INTERACTION P.A. Polivanov, А.А. Sidorenko, A.A. Maslov

More information

Part 3. Stability and Transition

Part 3. Stability and Transition Part 3 Stability and Transition 281 Overview T. Cebeci 1 Recent interest in the reduction of drag of underwater vehicles and aircraft components has rekindled research in the area of stability and transition.

More information

Broadband Noise reduction from a mini-uav propeller through boundary layer tripping

Broadband Noise reduction from a mini-uav propeller through boundary layer tripping Acoustics 2008 Geelong, Victoria, Australia 24 to 26 November 2008 Acoustics and Sustainability: How should acoustics adapt to meet future demands? Broadband Noise reduction from a mini-uav propeller through

More information

Chapter 5 Phenomena of laminar-turbulent boundary layer transition (including free shear layers)

Chapter 5 Phenomena of laminar-turbulent boundary layer transition (including free shear layers) Chapter 5 Phenomena of laminar-turbulent boundary layer transition (including free shear layers) T-S Leu May. 3, 2018 Chapter 5: Phenomena of laminar-turbulent boundary layer transition (including free

More information

Trailing edge noise prediction for rotating serrated blades

Trailing edge noise prediction for rotating serrated blades Trailing edge noise prediction for rotating serrated blades Samuel Sinayoko 1 Mahdi Azarpeyvand 2 Benshuai Lyu 3 1 University of Southampton, UK 2 University of Bristol, UK 3 University of Cambridge, UK

More information

Computation of trailing-edge aeroacoustics with vortex shedding

Computation of trailing-edge aeroacoustics with vortex shedding Center for Turbulence Research Annual Research Briefs 5 379 Computation of trailing-edge aeroacoustics with vortex shedding By M. Wang. Motivation and objectives The prediction and control of noise generated

More information

University of Bristol - Explore Bristol Research. Peer reviewed version. Link to publication record in Explore Bristol Research PDF-document

University of Bristol - Explore Bristol Research. Peer reviewed version. Link to publication record in Explore Bristol Research PDF-document Szke, M., & Azarpeyvand, M. (216). Trailing edge noise measurement: assumptions and uncertainties. Paper presented at 23rd International Congress on Sound and Vibration, Athens, Greece. Peer reviewed version

More information

LES of the trailing-edge flow and noise of a NACA0012 airfoil near stall

LES of the trailing-edge flow and noise of a NACA0012 airfoil near stall Center for Turbulence Research Proceedings of the Summer Program 8 7 LES of the trailing-edge flow and noise of a NACA airfoil near stall By S. Moreau, J. Christophe AND M. Roger Reynolds-averaged Navier-Stokes

More information

Investigation of the unsteady flow and noise sources generation in a slat cove: hybrid zonal RANS/LES simulation and dedicated experiment

Investigation of the unsteady flow and noise sources generation in a slat cove: hybrid zonal RANS/LES simulation and dedicated experiment 20th AIAA Computational Fluid Dynamics Conference 27-30 June 2011, Honolulu, Hawaii AIAA 2011-3203 Investigation of the unsteady flow and noise sources generation in a slat cove: hybrid zonal RANS/LES

More information

FLOW STRUCTURES AND PRESSURE FLUCTUATIONS IN A TIP LEAKAGE FLOW Roberto Camussi 1, Marc C. Jacob 2, Julien Grilliat 1,2 and Giovanni Caputi-Gennaro 1

FLOW STRUCTURES AND PRESSURE FLUCTUATIONS IN A TIP LEAKAGE FLOW Roberto Camussi 1, Marc C. Jacob 2, Julien Grilliat 1,2 and Giovanni Caputi-Gennaro 1 FLOW STRUCTURES AND PRESSURE FLUCTUATIONS IN A TIP LEAKAGE FLOW Roberto Camussi 1, Marc C. Jacob 2, Julien Grilliat 1,2 and Giovanni Caputi-Gennaro 1 1 Mechanical and Industrial Engineering Dept. (DIMI),

More information

A Low-Frequency Instability/Oscillation near the Airfoil Leading-Edge at Low Reynolds Numbers and Moderate Incidences

A Low-Frequency Instability/Oscillation near the Airfoil Leading-Edge at Low Reynolds Numbers and Moderate Incidences 20th AIAA Computational Fluid Dynamics Conference 27-30 June 2011, Honolulu, Hawaii AIAA 2011-3548 A Low-Frequency Instability/Oscillation near the Airfoil Leading-Edge at Low Reynolds Numbers and Moderate

More information

Porous Airfoils: Noise Reduction and Boundary Layer

Porous Airfoils: Noise Reduction and Boundary Layer 15th AIAA/CEAS Aeroacoustics Conference (3th AIAA Aeroacoustics Conference) 11-13 May 29, Miami, Florida AIAA 29-3392 Porous Airfoils: Noise Reduction and Boundary Layer Effects Thomas Geyer Ennes Sarradj

More information

UNSTEADY DISTURBANCE GENERATION AND AMPLIFICATION IN THE BOUNDARY-LAYER FLOW BEHIND A MEDIUM-SIZED ROUGHNESS ELEMENT

UNSTEADY DISTURBANCE GENERATION AND AMPLIFICATION IN THE BOUNDARY-LAYER FLOW BEHIND A MEDIUM-SIZED ROUGHNESS ELEMENT UNSTEADY DISTURBANCE GENERATION AND AMPLIFICATION IN THE BOUNDARY-LAYER FLOW BEHIND A MEDIUM-SIZED ROUGHNESS ELEMENT Ulrich Rist and Anke Jäger Institut für Aerodynamik und Gasdynamik, Universität Stuttgart,

More information

LANDING GEARS AERODYNAMIC INTERACTION NOISE

LANDING GEARS AERODYNAMIC INTERACTION NOISE European Congress on Computational Methods in Applied Sciences and Engineering ECCOMAS 2004 P. Neittaanmäki, T. Rossi, S. Korotov, E. Oñate, J. Périaux, and D. Knörzer (eds.) Jyväskylä, 24 28 July 2004

More information

Spatial Evolution of Resonant Harmonic Mode Triads in a Blasius Boundary Layer

Spatial Evolution of Resonant Harmonic Mode Triads in a Blasius Boundary Layer B Spatial Evolution of esonant Harmonic Mode Triads in a Blasius Boundary Layer José B. Dávila * Trinity College, Hartford, Connecticut 66 USA and udolph A. King NASA Langley esearch Center, Hampton, Virginia

More information

Aeroacoustic Study of an Axial Ring Fan Using Lattice- Boltzmann Simulations

Aeroacoustic Study of an Axial Ring Fan Using Lattice- Boltzmann Simulations Aeroacoustic Study of an Axial Ring Fan Using Lattice- Boltzmann Simulations Dominic Lallier-Daniels, Department of Mechanical Enginering, Université de Sherbrooke, Sherbrooke, Quebec, Canada Mélanie Piellard,

More information

Fan Blade Trailing-Edge Noise Prediction Using RANS Simulations

Fan Blade Trailing-Edge Noise Prediction Using RANS Simulations Acoustics 8 Paris Fan Blade Trailing-Edge Noise Prediction Using RANS Simulations Y. Rozenberg a, M. Roger b and S. Moreau c a ONERA, BP 72-29 avenue de la Division Leclerc, 92322 Chatillon Cedex, France

More information

Z. Zuo, Q. Huang and S. Liu

Z. Zuo, Q. Huang and S. Liu Journal of Applied Fluid Mechanics, Vol. 1, No., pp. 37-339, 019. Available online at www.jafmonline.net, ISSN 1735-357, EISSN 1735-3645. DOI: 10.18869/acadpub.jafm.75.54.914 An Analysis on the Flow Field

More information

Numerical simulations of the edge tone

Numerical simulations of the edge tone Numerical simulations of the edge tone I. Vaik, G. Paál Department of Hydrodynamic Systems, Budapest University of Technology and Economics, P.O. Box 91., 1521 Budapest, Hungary, {vaik, paal}@vizgep.bme.hu

More information

Studies on the Transition of the Flow Oscillations over an Axisymmetric Open Cavity Model

Studies on the Transition of the Flow Oscillations over an Axisymmetric Open Cavity Model Advances in Aerospace Science and Applications. ISSN 2277-3223 Volume 3, Number 2 (2013), pp. 83-90 Research India Publications http://www.ripublication.com/aasa.htm Studies on the Transition of the Flow

More information

Effects of Free-Stream Vorticity on the Blasius Boundary Layer

Effects of Free-Stream Vorticity on the Blasius Boundary Layer 17 th Australasian Fluid Mechanics Conference Auckland, New Zealand 5-9 December 2010 Effects of Free-Stream Vorticity on the Boundary Layer D.A. Pook, J.H. Watmuff School of Aerospace, Mechanical & Manufacturing

More information

Improvements of a parametric model for fan broadband and tonal noise

Improvements of a parametric model for fan broadband and tonal noise Improvements of a parametric model for fan broadband and tonal noise A. Moreau and L. Enghardt DLR - German Aerospace Center, Mueller-Breslau-Str. 8, 10623 Berlin, Germany antoine.moreau@dlr.de 4083 Engine

More information

INVESTIGATION OF AIRFOIL TRAILING EDGE NOISE WITH ADVANCED EXPERIMENTAL AND NUMERICAL METHODS

INVESTIGATION OF AIRFOIL TRAILING EDGE NOISE WITH ADVANCED EXPERIMENTAL AND NUMERICAL METHODS The 21 st International Congress on Sound and Vibration 13-17 July, 214, Beijing/China INVESTIGATION OF AIRFOIL TRAILING EDGE NOISE WITH ADVANCED EXPERIMENTAL AND NUMERICAL METHODS Tom Gerhard and Thomas

More information

Fan Stage Broadband Noise Benchmarking Programme

Fan Stage Broadband Noise Benchmarking Programme Fan Stage Broadband Noise Benchmarking Programme Specification of Fundamental Test Case 3 (FC3) Version 1 : 26 January 2015 Test Case Coordinator John Coupland ISVR University of Southampton UK E-mail

More information

Flow visualization of swept wing boundary layer transition

Flow visualization of swept wing boundary layer transition 1 th Pacific Symposium on Flow Visualization and Image Processing Naples, Italy, 15-18 June, 215 Flow visualization of swept wing boundary layer transition Jacopo Serpieri 1,* and Marios Kotsonis 1 1 Department

More information

EXPERIMENTS OF CROSS-FLOW INSTABILITY IN A SWEPT-WING BOUNDARY LAYER

EXPERIMENTS OF CROSS-FLOW INSTABILITY IN A SWEPT-WING BOUNDARY LAYER 27 TH INTERNATIONAL CONGRESS OF THE AERONAUTICAL SCIENCES EXPERIMENTS OF CROSS-FLOW INSTABILITY IN A SWEPT-WING BOUNDARY LAYER Zuo Sui-han*, Yang Yong*, Li Dong* *National Key Laboratory of Science and

More information

arxiv: v1 [physics.flu-dyn] 25 Dec 2018

arxiv: v1 [physics.flu-dyn] 25 Dec 2018 Self-Noise modelling and acoustic scaling of an axial fan configured with rotating controlled diffusion blade Behdad Davoudi 1 and Scott C. Morris 2 arxiv:1812.10003v1 [physics.flu-dyn] 25 Dec 2018 Abstract

More information

Direct Numerical Simulations of Transitional Flow in Turbomachinery

Direct Numerical Simulations of Transitional Flow in Turbomachinery Direct Numerical Simulations of Transitional Flow in Turbomachinery J.G. Wissink and W. Rodi Institute for Hydromechanics University of Karlsruhe Unsteady transitional flow over turbine blades Periodic

More information

Numerical study of the effects of trailing-edge bluntness on highly turbulent hydro-foil flows

Numerical study of the effects of trailing-edge bluntness on highly turbulent hydro-foil flows Numerical study of the effects of trailing-edge bluntness on highly turbulent hydro-foil flows T. Do L. Chen J. Tu B. Anderson 7 November 2005 Abstract Flow-induced noise from fully submerged lifting bodies

More information

Unsteady Volumetric Entropy Generation Rate in Laminar Boundary Layers

Unsteady Volumetric Entropy Generation Rate in Laminar Boundary Layers Entropy 6, 8[], 5-3 5 Entropy ISSN 99-43 www.mdpi.org/entropy/ Unsteady Volumetric Entropy Generation Rate in Laminar Boundary Layers E. J. Walsh & D. Hernon Stokes Research Institute, Dept. of Mechanical

More information

Trailing Edge Noise Computation of a Fan Blade Profile

Trailing Edge Noise Computation of a Fan Blade Profile 1ème Congrès Français d Acoustique Lyon, 12-16 Avril 21 Trailing Edge Noise Computation of a Fan Blade Profile Julien Christophe 1,Stéphane Moreau 2,Jérome Anthoine 2 1 von Karman Institute for Fluid Dynamics,

More information

Measurement and Scaling of Trailing-Edge Noise * *rather an extensive look at the scaling of the related source quantities Michaela Herr

Measurement and Scaling of Trailing-Edge Noise * *rather an extensive look at the scaling of the related source quantities Michaela Herr Measurement and Scaling of Trailing-Edge Noise * *rather an extensive look at the scaling of the related source quantities Michaela Herr Institute of Aerodynamics and Flow Technology DLR Braunschweig 13

More information

Large-Eddy Simulation and Trailing-Edge Noise Prediction of an Airfoil with Boundary-Layer Tripping

Large-Eddy Simulation and Trailing-Edge Noise Prediction of an Airfoil with Boundary-Layer Tripping 15th AIAA/CEAS Aeroacoustics Conference (3th AIAA Aeroacoustics Conference) 11-13 May 9, Miami, Florida AIAA 9-3197 Large-Eddy Simulation and Trailing-Edge Noise Prediction of an Airfoil with Boundary-Layer

More information

Active Control of Separated Cascade Flow

Active Control of Separated Cascade Flow Chapter 5 Active Control of Separated Cascade Flow In this chapter, the possibility of active control using a synthetic jet applied to an unconventional axial stator-rotor arrangement is investigated.

More information

FLOW VISUALIZATION AND PIV MEASUREMENTS OF LAMINAR SEPARATION BUBBLE OSCILLATING AT LOW FREQUENCY ON AN AIRFOIL NEAR STALL

FLOW VISUALIZATION AND PIV MEASUREMENTS OF LAMINAR SEPARATION BUBBLE OSCILLATING AT LOW FREQUENCY ON AN AIRFOIL NEAR STALL 4 TH INTERNATIONAL CONGRESS OF THE AERONAUTICAL SCIENCES FLOW VISUALIZATION AND PIV MEASUREMENTS OF LAMINAR SEPARATION BUBBLE OSCILLATING AT LOW FREQUENCY ON AN AIRFOIL NEAR STALL Hiroyuki Tanaka Department

More information

Beamforming of aeroacoustic sources in the time domain

Beamforming of aeroacoustic sources in the time domain Beamforming of aeroacoustic sources in the time domain Jeoffrey FISCHER 1 ; Vincent VALEAU 1 ; Laurent-Emmanuel BRIZZI 1 1 Institut PPRIME UPR 3346 CNRS - Université de Poitiers - ENSMA 86022 Poitiers

More information

University of Bristol - Explore Bristol Research. Peer reviewed version. Link to published version (if available): /6.

University of Bristol - Explore Bristol Research. Peer reviewed version. Link to published version (if available): /6. Afshari, A., Azarpeyvand, M., Dehghan, A. A., & Szoke, M. (2017). Effects of Streamwise Surface Treatments on Trailing Edge Noise Reduction. In 23rd AIAA/CEAS Aeroacoustics Conference [AIAA 2017-3499]

More information

THE EFFECT OF INTERNAL ACOUSTIC EXCITATION ON THE AERODYNAMIC CHARACTERISTICS OF AIRFOIL AT HIGH ANGLE OF ATTACKE

THE EFFECT OF INTERNAL ACOUSTIC EXCITATION ON THE AERODYNAMIC CHARACTERISTICS OF AIRFOIL AT HIGH ANGLE OF ATTACKE Vol.1, Issue.2, pp-371-384 ISSN: 2249-6645 THE EFFECT OF INTERNAL ACOUSTIC EXCITATION ON THE AERODYNAMIC CHARACTERISTICS OF AIRFOIL AT HIGH ANGLE OF ATTACKE Dr. Mohammed W. Khadim Mechanical Engineering

More information

Flap Edge Aeroacoustic Measurements and Predictions

Flap Edge Aeroacoustic Measurements and Predictions For permission to copy or republish, contact the 11 Alexander Bell Drive, Suite, Reston, VA 191 AIAA -1975 Flap Edge Aeroacoustic Measurements and Predictions Thomas F. Brooks and William M. Humphreys,

More information

Experimental investigation of separated shear layer from a leading edge subjected to various angles of attack with tail flap deflections

Experimental investigation of separated shear layer from a leading edge subjected to various angles of attack with tail flap deflections Sādhanā Vol. 40, Part 3, May 2015, pp. 803 817. c Indian Academy of Sciences Experimental investigation of separated shear layer from a leading edge subjected to various angles of attack with tail flap

More information

IN SEARCH OF THE PHYSICS: NASA s APPROACH TO AIRFRAME NOISE

IN SEARCH OF THE PHYSICS: NASA s APPROACH TO AIRFRAME NOISE IN SEARCH OF THE PHYSICS: NASA s APPROACH TO AIRFRAME NOISE Michele G. Macaraeg, David P. Lockard, and Craig L. Streett Aerodynamics, Aerothermodynamics, and Acoustics Competency NASA Langley Research

More information

Trailing edge noise of partially porous airfoils

Trailing edge noise of partially porous airfoils AIAA Aviation 16-2 June 214, Atlanta, GA 2th AIAA/CEAS Aeroacoustics Conference AIAA 214-339 Trailing edge noise of partially porous airfoils Thomas Geyer and Ennes Sarradj Brandenburg University of Technology

More information

LES of synthetic jets in boundary layer with laminar separation caused by adverse pressure gradient

LES of synthetic jets in boundary layer with laminar separation caused by adverse pressure gradient LES of synthetic jets in boundary layer with laminar separation caused by adverse pressure gradient Tetsuya Ozawa, Samuel Lesbros and Guang Hong* University of Technology, Sydney (UTS), Australia *Corresponding

More information

Experimental setup and data processing

Experimental setup and data processing NEW CPV-RESULTS OF NACA 0012 TRAILING-EDGE NOISE A. Herrig, W. Würz and E. Krämer, S. Wagner Institute of Aerodynamics und Gas Dynamics (IAG), University of Stuttgart, Pfaffenwaldring 21, D-70550 Stuttgart,

More information

INVESTIGATION OF 2D AND 3D BOUNDARY-LAYER DISTURBANCES FOR ACTIVE CONTROL OF LAMINAR SEPARATION BUBBLES

INVESTIGATION OF 2D AND 3D BOUNDARY-LAYER DISTURBANCES FOR ACTIVE CONTROL OF LAMINAR SEPARATION BUBBLES INVESTIGATION OF 2D AND 3D BOUNDARY-LAYER DISTURBANCES FOR ACTIVE CONTROL OF LAMINAR SEPARATION BUBBLES Kai Augustin, Ulrich Rist and Siegfried Wagner Institut für Aerodynamik und Gasdynamik, Universität

More information

Aerodynamic force analysis in high Reynolds number flows by Lamb vector integration

Aerodynamic force analysis in high Reynolds number flows by Lamb vector integration Aerodynamic force analysis in high Reynolds number flows by Lamb vector integration Claudio Marongiu, Renato Tognaccini 2 CIRA, Italian Center for Aerospace Research, Capua (CE), Italy E-mail: c.marongiu@cira.it

More information

Numerical Simulation of a Blunt Airfoil Wake

Numerical Simulation of a Blunt Airfoil Wake 6th Australasian Fluid Mechanics Conference Crown Plaza, Gold Coast, Australia 2-7 December 7 Numerical Simulation of a Blunt Airfoil Wake C.J. Doolan School of Mechanical Engineering University of Adelaide,

More information

Journal of Fluid Science and Technology

Journal of Fluid Science and Technology Science and Technology LDV and PIV Measurements of the Organized Oscillations of Turbulent Flow over a Rectangular Cavity* Takayuki MORI ** and Kenji NAGANUMA ** **Naval Systems Research Center, TRDI/Ministry

More information

Experimental Study of Near Wake Flow Behind a Rectangular Cylinder

Experimental Study of Near Wake Flow Behind a Rectangular Cylinder American Journal of Applied Sciences 5 (8): 97-926, 28 ISSN 546-9239 28 Science Publications Experimental Study of Near Wake Flow Behind a Rectangular Cylinder Abdollah Shadaram, Mahdi Azimi Fard and Noorallah

More information

Far Field Noise Minimization Using an Adjoint Approach

Far Field Noise Minimization Using an Adjoint Approach Far Field Noise Minimization Using an Adjoint Approach Markus P. Rumpfkeil and David W. Zingg University of Toronto Institute for Aerospace Studies 4925 Dufferin Street, Toronto, Ontario, M3H 5T6, Canada

More information

Keywords: Contoured side-walls, design, experimental, laminar boundary layer, numerical, receptivity, stability, swept wing, wind tunnel.

Keywords: Contoured side-walls, design, experimental, laminar boundary layer, numerical, receptivity, stability, swept wing, wind tunnel. Applied Mechanics and Materials Vol. 390 (2013) pp 96-102 Online available since 2013/Aug/30 at www.scientific.net (2013) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/amm.390.96

More information

APPLICATIONS OF FULLY-RESOLVED LARGE EDDY SIMULATION TO UNSTEADY FLUID FLOW AND AEROACOUSTICS PREDICTIONS

APPLICATIONS OF FULLY-RESOLVED LARGE EDDY SIMULATION TO UNSTEADY FLUID FLOW AND AEROACOUSTICS PREDICTIONS APPLICATIONS OF FULLY-RESOLVED LARGE EDDY SIMULATION TO UNSTEADY FLUID FLOW AND AEROACOUSTICS PREDICTIONS Chisachi Kato Institute of Industrial Science The University of Tokyo 4-6-1 Komaba, Meguro-ku,

More information

Effect of Flow-Acoustic Resonant Interactions on Aerodynamic Response of Transitional Airfoils

Effect of Flow-Acoustic Resonant Interactions on Aerodynamic Response of Transitional Airfoils Dissertations and Theses 12-2016 Effect of Flow-Acoustic Resonant Interactions on Aerodynamic Response of Transitional Airfoils Joseph Hayden Follow this and additional works at: https://commons.erau.edu/edt

More information

Power-Spectral density estimate of the Bloor-Gerrard instability in flows around circular cylinders

Power-Spectral density estimate of the Bloor-Gerrard instability in flows around circular cylinders Exp Fluids (2011) 50:527 534 DOI 10.1007/s00348-010-0955-4 RESEARCH ARTICLE Power-Spectral density estimate of the Bloor-Gerrard instability in flows around circular cylinders M. Khor J. Sheridan K. Hourigan

More information

inter.noise 2000 The 29th International Congress and Exhibition on Noise Control Engineering August 2000, Nice, FRANCE

inter.noise 2000 The 29th International Congress and Exhibition on Noise Control Engineering August 2000, Nice, FRANCE 1 inter.noise 2000 The 29th International Congress and Exhibition on Noise Control Engineering 27-30 August 2000, Nice, FRANCE I-INCE Classification: 1.0 PREDICTION OF LOW FREQUENCY SOUND GENERATION FROM

More information

High speed PIV applied to aerodynamic noise investigation

High speed PIV applied to aerodynamic noise investigation Exp Fluids (11) 5:863 876 DOI 1.17/s348-1-935-8 RESEARCH ARTICLE High speed applied to aerodynamic noise investigation V. Koschatzky P. D. Moore J. Westerweel F. Scarano B. J. Boersma Received: 11 December

More information

Generation of Downstream Vorticity Through the Use of Modified Trailing Edge Configurations

Generation of Downstream Vorticity Through the Use of Modified Trailing Edge Configurations Generation of Downstream Vorticity Through the Use of Modified Trailing Edge Configurations Benjamin Worrall Thesis submitted to the faculty of the Virginia Polytechnic Institute and State University in

More information

Evaluation of Aeroacoustic Noise Source Structure. around Panhead of a Pantograph in High-Speed Railway

Evaluation of Aeroacoustic Noise Source Structure. around Panhead of a Pantograph in High-Speed Railway Evaluation of Aeroacoustic Noise Source Structure around Panhead of a Pantograph in High-Speed Railway 1 M. Ikeda, 1 T. Mitsumoji 1 Railway Technical Research Institute, Tokyo, Japan Abstract: As the maimum

More information

ASSESSMENT OF ANISOTROPY IN THE NEAR FIELD OF A RECTANGULAR TURBULENT JET

ASSESSMENT OF ANISOTROPY IN THE NEAR FIELD OF A RECTANGULAR TURBULENT JET TUR-3 ExHFT-7 8 June 03 July 009, Krakow, Poland ASSESSMENT OF ANISOTROPY IN THE NEAR FIELD OF A RECTANGULAR TURBULENT JET Α. Cavo 1, G. Lemonis, T. Panidis 1, * 1 Laboratory of Applied Thermodynamics,

More information

Airfoil noise reductions through leading edge serrations

Airfoil noise reductions through leading edge serrations Airfoil noise reductions through leading edge serrations S. Narayanan 1,a, P. Chaitanya 1,b, S. Haeri 2,a, P. Joseph 1,c,*, J. W. Kim 2,b, C. Polacsek 3 University of Southampton, Highfield, Southampton-SO17

More information

aeroacoustics volume 8 number

aeroacoustics volume 8 number LES prediction of wall-pressure fluctuations and noise of a low-speed airfoil by Meng Wang, Stephane Moreau, Gianluca Iaccarino and Michel Roger reprinted from aeroacoustics volume 8 number 3 9 published

More information

Problem 4.3. Problem 4.4

Problem 4.3. Problem 4.4 Problem 4.3 Problem 4.4 Problem 4.5 Problem 4.6 Problem 4.7 This is forced convection flow over a streamlined body. Viscous (velocity) boundary layer approximations can be made if the Reynolds number Re

More information

This is an author-deposited version published in: Handle ID:.http://hdl.handle.net/10985/8905

This is an author-deposited version published in:  Handle ID:.http://hdl.handle.net/10985/8905 Science Arts & Métiers (SAM) is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. This is an author-deposited

More information

Local correlations for flap gap oscillatory blowing active flow control technology

Local correlations for flap gap oscillatory blowing active flow control technology Local correlations for flap gap oscillatory blowing active flow control technology Cătălin NAE* *Corresponding author INCAS - National Institute for Aerospace Research Elie Carafoli Bdul Iuliu Maniu 0,

More information

WAVEPACKETS IN TURBULENT FLOW OVER A NACA 4412 AIRFOIL

WAVEPACKETS IN TURBULENT FLOW OVER A NACA 4412 AIRFOIL WAVEPACKETS IN TURBULENT FLOW OVER A NACA 442 AIRFOIL Leandra I. Abreu, André V. G. Cavalieri, Philipp Schlatter, Ricardo Vinuesa, Dan Henningson Instituto Tecnológico de Aeronáutica, São José dos Campos,

More information

Vortex shedding from slender surface mounted pyramids

Vortex shedding from slender surface mounted pyramids Vortex shedding from slender surface mounted pyramids M. J. Morrison 1, R. J. Martinuzzi 3, E. Savory 1, G. A. Kopp 2 1 Department of Mechanical and Materials Engineering, University of Western Ontario,

More information

Three-dimensional span effects of highaspect ratio synthetic jet forcing for separation control on a low-reynolds number airfoil

Three-dimensional span effects of highaspect ratio synthetic jet forcing for separation control on a low-reynolds number airfoil TSpace Research Repository tspace.library.utoronto.ca Three-dimensional span effects of highaspect ratio synthetic jet forcing for separation control on a low-reynolds number airfoil Mark Feero, Philippe

More information

ADVERSE REYNOLDS NUMBER EFFECT ON MAXIMUM LIFT OF TWO DIMENSIONAL AIRFOILS

ADVERSE REYNOLDS NUMBER EFFECT ON MAXIMUM LIFT OF TWO DIMENSIONAL AIRFOILS ICAS 2 CONGRESS ADVERSE REYNOLDS NUMBER EFFECT ON MAXIMUM LIFT OF TWO DIMENSIONAL AIRFOILS Kenji YOSHIDA, Masayoshi NOGUCHI Advanced Technology Aircraft Project Center NATIONAL AEROSPACE LABORATORY 6-

More information

3D hot-wire measurements of a wind turbine wake

3D hot-wire measurements of a wind turbine wake 1 3D hot-wire measurements of a wind turbine wake Pål Egil Eriksen PhD candidate, NTNU/NOWITECH Per-Åge Krogstad NTNU 2 Outline of the presentation Experimental setup Measurement technique Time averaged

More information

An overview of Onera aeroacoustic activities in the framework of propellers and open rotors

An overview of Onera aeroacoustic activities in the framework of propellers and open rotors An overview of Onera aeroacoustic activities in the framework of propellers and open rotors Y. Delrieux Onera. Computational Fluid Dynamics and Aeroacoustics A.Chelius, A. Giauque, S. Canard-Caruana, F.

More information

Given a stream function for a cylinder in a uniform flow with circulation: a) Sketch the flow pattern in terms of streamlines.

Given a stream function for a cylinder in a uniform flow with circulation: a) Sketch the flow pattern in terms of streamlines. Question Given a stream function for a cylinder in a uniform flow with circulation: R Γ r ψ = U r sinθ + ln r π R a) Sketch the flow pattern in terms of streamlines. b) Derive an expression for the angular

More information

UNIT IV BOUNDARY LAYER AND FLOW THROUGH PIPES Definition of boundary layer Thickness and classification Displacement and momentum thickness Development of laminar and turbulent flows in circular pipes

More information

Active Control of Turbulence and Fluid- Structure Interactions

Active Control of Turbulence and Fluid- Structure Interactions Bonjour! Active Control of Turbulence and Fluid- Structure Interactions Yu Zhou Institute for Turbulence-Noise-Vibration Interaction and Control Shenzhen Graduate School, Harbin Institute of Technology

More information

FUNDAMENTAL INVESTIGATIONS OF AIRFRAME NOISE 1. M.G. Macaraeg 2 NASA Langley Research Center Hampton, VA, USA

FUNDAMENTAL INVESTIGATIONS OF AIRFRAME NOISE 1. M.G. Macaraeg 2 NASA Langley Research Center Hampton, VA, USA FUNDAMENTAL INVESTIGATIONS OF AIRFRAME NOISE 1 M.G. Macaraeg 2 NASA Langley Research Center Hampton, VA, USA Abstract An extensive numerical and experimental study of airframe noise mechanisms associated

More information

Application of a Helmholtz resonator excited by grazing flow for manipulation of a turbulent boundary layer

Application of a Helmholtz resonator excited by grazing flow for manipulation of a turbulent boundary layer Application of a Helmholtz resonator excited by grazing flow for manipulation of a turbulent boundary layer Farzin Ghanadi School of Mechanical Engineering The University of Adelaide South Australia, 5005

More information

AN UNSTEADY AND TIME-AVERAGED STUDY OF A GROUND VORTEX FLOW

AN UNSTEADY AND TIME-AVERAGED STUDY OF A GROUND VORTEX FLOW 24 TH INTERNATIONAL CONGRESS OF THE AERONAUTICAL SCIENCES AN UNSTEADY AND TIME-AVERAGED STUDY OF A GROUND VORTEX FLOW N J Lawson*, J M Eyles**, K Knowles** *College of Aeronautics, Cranfield University,

More information

Aeroacoustic and Aerodynamics of Swirling Flows*

Aeroacoustic and Aerodynamics of Swirling Flows* Aeroacoustic and Aerodynamics of Swirling Flows* Hafiz M. Atassi University of Notre Dame * supported by ONR grant and OAIAC OVERVIEW OF PRESENTATION Disturbances in Swirling Flows Normal Mode Analysis

More information