TY - CHAP A1 - Guseva, Anastasia A1 - Hoffmann, Maik A1 - Unger, Alexander A1 - Zulk, Silvia A1 - El Amien, Mohamed Balla A1 - Sarradj, Ennes A1 - Kupnik, Mario T1 - Ultrasonic transducer characterization in air based on an indirect acoustic radiation pressure measurement T2 - IEEE International Ultrasonics Symposium (IUS), 21–24 October 2015, Taipei, Taiwan Y1 - 2015 U6 - https://doi.org/10.1109/ULTSYM.2015.0333 SP - 1 EP - 4 PB - IEEE ER - TY - CHAP A1 - Haase, Florian Vincent A1 - Dierl, Adrian A1 - Henke, Anna A1 - Woll, Ralf A1 - Sarradj, Ennes ED - Dahlgaard-Park, Su Mi ED - Dahlgaard, Jens Jörn T1 - Development of an experiment for impedance measurement of structured sandwich sheet metals by using a full factorial multi-stage approach T2 - Proceedings, 19th QMOD-ICQSS Conference International Conference on Quality and Service Sciences, Rom (Italy) Y1 - 2016 UR - https://www-docs.b-tu.de/fg-akustik/public/veroeffentlichungen/haase_impedancemeasurement_qmod2016.pdf SN - 978-91-7623-086-2 SP - 448 EP - 462 PB - Lund University Library Press CY - Lund ER - TY - GEN A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Circular Cylinders with Soft Porous Cover for Flow Noise Reduction T2 - Experiments in Fluids N2 - The use of porous materials is one of several approaches to passively control or minimize the generation of flow noise. In order to investigate the possible reduction of noise from struts and other protruding parts (for example components of the landing gear or pantographs), acoustic measurements were taken in a small aeroacoustic wind tunnel on a set of circular cylinders with a soft porous cover. The aim of this study was to identify those materials that result in the best noise reduction, which refers to both tonal noise and broadband noise. The porous covers were characterized by their air flow resistivity, a parameter describing the permeability of an open-porous material. The results show that materials with low air flow resistivities lead to a noticeable flow noise reduction. Thereby, the main effect of the porous cylinder covers is that the spectral peak of the aeolian tone due to vortex shedding appears much narrower, but is not suppressed completely. Based on the measurement results, a basic model for the estimation of the total peak level of the aeolian tone was derived. In addition to the minimization of the vortex shedding noise, a reduction of broadband noise can be observed, especially at higher Reynolds numbers. The noise reduction increases with decreasing air flow resistivity of the porous covers, which means that materials that are highly permeable to air result in the best noise reduction. Y1 - 2016 U6 - https://doi.org/10.1007/s00348-016-2119-7 SN - 0723-4864 VL - 57 IS - 3 SP - 30 ER - TY - GEN A1 - Geyer, Thomas A1 - Wasala, Sahan A1 - Cater, John A1 - Norris, Stuart A1 - Sarradj, Ennes T1 - Experimental Investigation of Leading Edge Hook Structures for Wind Turbine Noise Reduction : AIAA paper 2016-2954 T2 - 22nd AIAA/CEAS Aeroacoustics Conference 2016, Lyon, France, 30 May-1 June 2016, Vol. 5 Y1 - 2016 SN - 978-1-5108-2672-4 SP - 3853 EP - 3865 PB - Curran Associates CY - Red Hook, NY ER - TY - GEN A1 - Geyer, Thomas A1 - Claus, Vanessa A1 - Sarradj, Ennes A1 - Markus, Philipp T1 - Silent Owl Flight: The Effect of the Leading Edge Comb on the Gliding Flight Noise : AIAA paper 2016-3017 T2 - 22nd AIAA/CEAS Aeroacoustics Conference 2016, Lyon, France, 30 May-1 June 2016, vol. 7 Y1 - 2016 SN - 978-1-5108-2672-4 SP - 4885 EP - 4896 PB - Curran Associates CY - Red Hook, NY ER - TY - GEN A1 - Herold, Gert A1 - Zenger, Florian A1 - Sarradj, Ennes T1 - Analyzing Noise Components on Skewed Fans with a Virtual Rotating Microphone Array : AIAA paper 2016-2761 T2 - 22nd AIAA/CEAS Aeroacoustics Conference 2016, Lyon, France, 30 May-1 June 2016 Y1 - 2016 SN - 978-1-5108-2672-4 PB - Curran Associates CY - Red Hook, NY ER - TY - GEN A1 - Sarradj, Ennes T1 - A Fast Ray Casting Method for Sound Refraction at Shear Layers : AIAA paper 2016-2762 T2 - 22nd AIAA/CEAS Aeroacoustics Conference 2016, Lyon, France, 30 May-1 June 2016, vol. 2 Y1 - 2016 SN - 978-1-5108-2672-4 SP - 981 EP - 990 PB - Curran Associates CY - Red Hook, NY ER - TY - CHAP A1 - Herold, Gert A1 - Sarradj, Ennes T1 - Frequency Domain Deconvolution for Rotating Sources on an Axial Fan T2 - BeBeC, 6th Berlin Beamforming Conference, February 29 - March 1, 2016, proceedings Y1 - 2016 PB - Berlin CY - Gesellschaft zur Förderung angewandter Informatik ER - TY - CHAP A1 - Sarradj, Ennes T1 - A Generic Approach to Synthesize Optimal Array Microphone Arrangements T2 - BeBeC, 6th Berlin Beamforming Conference, February 29 - March 1, 2016, proceedings Y1 - 2016 PB - Berlin CY - Gesellschaft zur Förderung angewandter Informatik ER - TY - GEN A1 - Zenger, Florian A1 - Herold, Gert A1 - Becker, Stefan A1 - Sarradj, Ennes T1 - Sound source localization on an axial fan at different operating points T2 - Experiments in Fluids Y1 - 2016 U6 - https://doi.org/10.1007/s00348-016-2223-8 SN - 0723-4864 SN - 1432-1114 VL - 57 SP - 136 ER - TY - CHAP A1 - Geyer, Thomas A1 - Sarradj, Ennes A1 - Hobracht, Marcus ED - Kropp, Wolfgang ED - Estorff, Otto von ED - Schulte-Fortkamp, Brigitte T1 - Noise generated by a leading edge in anisotropic turbulence T2 - 45th International Congress and Exposition on Noise Control Engineering (Internoise 2016), Hamburg, Germany, 21-24 August 2016, vol. 8 Y1 - 2016 SN - 978-1-5108-2988-6 SP - 6067 EP - 6078 PB - Curran Associates CY - Red Hook, NY ER - TY - CHAP A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Experimentelle Untersuchung der Minderung von Strömungsschall durch poröse Zylinderummantelungen T2 - Fortschritte der Akustik, DAGA 2016, Aachen, 14.-17. März 2016, 42. Jahrestagung für Akustik Y1 - 2016 SN - 978-3-939296-10-2 PB - DAGA CY - Berlin ER - TY - GEN A1 - Kamps, Laura A1 - Geyer, Thomas A1 - Sarradj, Ennes A1 - Brücker, Christoph T1 - Vortex shedding noise of a cylinder with hairy flaps T2 - Journal of Sound and Vibration Y1 - 2017 U6 - https://doi.org/10.1016/j.jsv.2016.10.039 SN - 0022-460X VL - 388 SP - 69 EP - 84 ER - TY - CHAP A1 - Brücker, Christoph A1 - Kamps, Laura A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Wake-Vortex Sound Attenuation using Attached Hairy Flaps T2 - Fortschritte der Akustik, DAGA 2016, Aachen, 14.-17. März 2016, 42. Jahrestagung für Akustik Y1 - 2016 SN - 978-3-939296-10-2 PB - DAGA CY - Berlin ER - TY - CHAP A1 - Henke, Anna-Sophia A1 - Sarradj, Ennes T1 - Punktimpedanzen strukturierter Doppelbleche T2 - Fortschritte der Akustik, DAGA 2016, Aachen, 14.-17. März 2016, 42. Jahrestagung für Akustik Y1 - 2016 SN - 978-3-939296-10-2 PB - DAGA CY - Berlin ER - TY - CHAP A1 - Herold, Gert A1 - Sarradj, Ennes T1 - Acoular - Open-Source-Software zur Anwendung von Mikrofonarrayverfahren T2 - Fortschritte der Akustik, DAGA 2016, Aachen, 14.-17. März 2016, 42. Jahrestagung für Akustik Y1 - 2016 SN - 978-3-939296-10-2 PB - DAGA CY - Berlin ER - TY - CHAP A1 - Sarradj, Ennes A1 - Meiselbach, Falko T. T1 - Berechnung von Schalldämpfern mit Platten- oder Membran-Auskleidung T2 - Fortschritte der Akustik, DAGA 2016, Aachen, 14.-17. März 2016, 42. Jahrestagung für Akustik Y1 - 2016 SN - 978-3-939296-10-2 PB - DAGA CY - Berlin ER - TY - CHAP A1 - Schulze, Thomas A1 - Sarradj, Ennes A1 - Geyer, Thomas T1 - Windgeräuschreduktion am Ohr T2 - Fortschritte der Akustik, DAGA 2016, Aachen, 14.-17. März 2016, 42. Jahrestagung für Akustik Y1 - 2016 SN - 978-3-939296-10-2 PB - DAGA CY - Berlin ER - TY - GEN A1 - Sarradj, Ennes A1 - Herold, Gert T1 - A Python framework for microphone array data processing T2 - Applied Acoustics Y1 - 2016 U6 - https://doi.org/10.1016/j.apacoust.2016.09.015 SN - 0003-682X VL - 116 SP - 50 EP - 58 ER - TY - GEN A1 - Herold, Gert A1 - Geyer, Thomas A1 - Markus, Philipp A1 - Sarradj, Ennes T1 - Simultaneous Sound Power Measurement of Engine Components T2 - SAE International Journal of Passenger Cars - Mechanical Systems Y1 - 2016 U6 - https://doi.org/10.4271/2016-01-1774 SN - 1946-3995 SN - 1946-4002 VL - 9 IS - 3 SP - 974 EP - 979 ER - TY - CHAP A1 - Sharma, Sparsh A1 - Sarradj, Ennes A1 - Schmidt, Heiko T1 - Unsteady Lift due to the Interaction of Incidence Turbulence with an Airfoil T2 - Fortschritte der Akustik, 43. Deutsche Jahrestagung für Akus tik, 6.-9. März 2017 in Kiel Y1 - 2017 UR - https://www.dega-akustik.de/fileadmin/dega-akustik.de/publikationen/DAGA/DAGA_17_Inhalt.pdf SN - 978-3-939296-12-6 SP - 1489 EP - 1490 PB - Deutsche Gesellschaft für Akustik e.V. (DEGA) CY - Berlin ER - TY - CHAP A1 - Schulz, Adrian A1 - Geyer, Thomas A1 - Thürmer, Konrad A1 - Sarradj, Ennes A1 - Stapel, Jennifer T1 - Beachtung der Schallemission wasserwirtschaftlicher Anlagen im urbanen Raum T2 - Bemessung im Wasserbau, Klimaanpassung, Unersuchungen, Regeln, Planung, Ausführung, 40. Dresdner Wasserbaukolloquium 2017, 09.-10. März 2017 Y1 - 2017 SN - 978-3-86780-509-4 SP - 201 EP - 210 PB - Selbstverlag der Technischen Universität Dresden CY - Dresden ER - TY - CHAP A1 - Geyer, Thomas A1 - Sarradj, Ennes A1 - Winkler, Peggy T1 - Messungen an einem Modell-Propellerprüfstand T2 - Fortschritte der Akustik, 43. Deutsche Jahrestagung für Akus tik, 6.-9. März 2017 in Kiel Y1 - 2017 UR - https://www.dega-akustik.de/fileadmin/dega-akustik.de/publikationen/DAGA/DAGA_17_Inhalt.pdf SN - 978-3-939296-12-6 SP - 983 EP - 986 PB - Deutsche Gesellschaft für Akustik e.V. (DEGA) CY - Berlin ER - TY - CHAP A1 - Hall, Philipp A1 - Herold, Gert A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Vergleich verschiedener Methoden zur Schallleistungsbestimmung von Maschinenkomponenten T2 - Fortschritte der Akustik, 43. Deutsche Jahrestagung für Akus tik, 6.-9. März 2017 in Kiel Y1 - 2017 UR - https://www.dega-akustik.de/fileadmin/dega-akustik.de/publikationen/DAGA/DAGA_17_Inhalt.pdf SN - 978-3-939296-12-6 SP - 564 EP - 567 PB - Deutsche Gesellschaft für Akustik e.V. (DEGA) CY - Berlin ER - TY - CHAP A1 - Kisler, Roman A1 - Sarradj, Ennes T1 - Modellierung der Schalldämpfung mehrschichtiger Plattenresonatoren in Strömungskanälen T2 - Fortschritte der Akustik, 43. Deutsche Jahrestagung für Akus tik, 6.-9. März 2017 in Kiel Y1 - 2017 UR - https://www.dega-akustik.de/fileadmin/dega-akustik.de/publikationen/DAGA/DAGA_17_Inhalt.pdf SN - 978-3-939296-12-6 SP - 1545 EP - 1548 PB - Deutsche Gesellschaft für Akustik e.V. (DEGA) CY - Berlin ER - TY - GEN A1 - Geyer, Thomas A1 - Kamps, Laura A1 - Sarradj, Ennes A1 - Brücker, Christoph T1 - Passive Control of the Vortex Shedding Noise of a Cylinder at Low Reynolds Numbers Using Flexible Flaps T2 - 23rd AIAA/CEAS Aeroacoustics Conference 2017, Denver, USA, 5 June - 9 June 2017, (AIAA 2017-3015) Y1 - 2017 UR - https://arc.aiaa.org/doi/abs/10.2514/6.2017-3015 SN - 978-1-62410-504-3 PB - AIAA CY - Reston, Va ER - TY - GEN A1 - Moreau, Danielle J. A1 - Geyer, Thomas A1 - Doolan, Con A1 - Sarradj, Ennes T1 - Camber Effects on the Tonal Noise and Flow Characteristics of a Wall-mounted Finite Airfoil T2 - 23rd AIAA/CEAS Aeroacoustics Conference 2017, Denver, USA, 5 June - 9 June 2017, (AIAA 2017-3172) Y1 - 2017 UR - https://arc.aiaa.org/doi/abs/10.2514/6.2017-3172 SN - 978-1-62410-504-3 PB - AIAA CY - Reston, Va ER - TY - GEN A1 - Kamps, Laura A1 - Brücker, Christoph A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Airfoil Self Noise Reduction at Low Reynolds Numbers Using a Passive Flexible Trailing Edge T2 - 23rd AIAA/CEAS Aeroacoustics Conference 2017, Denver, USA, 5 June - 9 June 2017, (AIAA 2017-3496) Y1 - 2017 UR - https://arc.aiaa.org/doi/abs/10.2514/6.2017-3496 SN - 978-1-62410-504-3 PB - AIAA CY - Reston, Va ER - TY - GEN A1 - Sarradj, Ennes A1 - Herold, Gert A1 - Sijtsma, Pieter A1 - Merino-Martinez, Roberto A1 - Geyer, Thomas A1 - Bahr, Christopher A1 - Porteous, Ric A1 - Moreau, Danielle J. A1 - Doolan, Con T1 - A Microphone Array Method Benchmarking Exercise using Synthesized Input Data T2 - 23rd AIAA/CEAS Aeroacoustics Conference 2017, Denver, USA, 5 June - 9 June 2017, (AIAA 2017-3719) Y1 - 2017 UR - https://arc.aiaa.org/doi/pdfplus/10.2514/6.2017-3719 SN - 978-1-62410-504-3 PB - AIAA CY - Reston, Va ER - TY - GEN A1 - Herold, Gert A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Comparison of Inverse Deconvolution Algorithms for High-resolution Aeroacoustic Source Characterization T2 - 23rd AIAA/CEAS Aeroacoustics Conference 2017, Denver, USA, 5 June - 9 June 2017, (AIAA 2017-4177) Y1 - 2017 UR - https://arc.aiaa.org/doi/abs/10.2514/6.2017-4177 SN - 978-1-62410-504-3 PB - AIAA CY - Reston, Va ER - TY - GEN A1 - Geyer, Thomas A1 - Claus, Vanessa A1 - Hall, Philipp A1 - Sarradj, Ennes T1 - Silent Owl Flight: The Effect of the Leading Edge Comb T2 - International Journal of Aeroacoustics Y1 - 2017 SN - 2048-4003 VL - 16 IS - 3 SP - 115 EP - 134 ER - TY - GEN A1 - Geyer, Thomas A1 - Schulz, Adrian A1 - Thürmer, Konrad A1 - Sarradj, Ennes A1 - Stapel, Jennifer T1 - Schallemission wasserwirtschaftlicher Anlagen T2 - Lärmbekämpfung Y1 - 2017 SN - 1436-4999 IS - 3 SP - 99 EP - 103 ER - TY - CHAP A1 - Moreau, Danielle J. A1 - Geyer, Thomas A1 - Doolan, Con A1 - Sarradj, Ennes T1 - Influence of Camber on Wall-Mounted Finite Airfoil Tonal Noise Generation T2 - 4th Symposium on Fluid-Structure-Sound Interactions and Control, Tokio, 2017 Y1 - 2018 SN - 978-981-10-7542-1 SN - 978-981-10-7541-4 SP - 337 EP - 342 PB - Springer CY - Singapore ER - TY - GEN A1 - Geyer, Thomas A1 - Poppe, Willi A1 - Sarradj, Ennes T1 - Measurement of flow noise generation and pressure loss of nets and screens T2 - Applied Acoustics Y1 - 2018 U6 - https://doi.org/10.1016/j.apacoust.2018.01.008 SN - 0003-682X VL - 134 SP - 69 EP - 74 ER - TY - GEN A1 - Henke, Anna-Sophia A1 - Sarradj, Ennes A1 - Langhof, Carsten T1 - Driving-point mobility and sound insulation of structured sheet metal T2 - Applied Acoustics Y1 - 2018 SN - 0003-682X VL - 136 SP - 113 EP - 122 ER - TY - GEN A1 - Hoeltgen, Laurent A1 - Breuß, Michael A1 - Herold, Gert A1 - Sarradj, Ennes T1 - Sparse ℓ1 regularisation of matrix valued models for acoustic source characterisation T2 - Optimization and Engineering N2 - We present a strategy for the recovery of a sparse solution of a common problem in acoustic engineering, which is the reconstruction of sound source levels and locations applying microphone array measurements. The considered task bears similarities to the basis pursuit formalism but also relies on additional model assumptions that are challenging from a mathematical point of view. Our approach reformulates the original task as a convex optimisation model. The sought solution shall be a matrix with a certain desired structure. We enforce this structure through additional constraints. By combining popular splitting algorithms and matrix differential theory in a novel framework we obtain a numerically efficient strategy. Besides a thorough theoretical consideration we also provide an experimental setup that certifies the usability of our strategy. Finally, we also address practical issues, such as the handling of inaccuracies in the measurement and corruption of the given data. We provide a post processing step that is capable of yielding an almost perfect solution in such circumstances. KW - Convex optimisation KW - Sparse recovery KW - Split Bregman KW - Microphone array KW - Matrix differentiation KW - Acoustic source characterisation Y1 - 2018 U6 - https://doi.org/10.1007/s11081-017-9357-2 SN - 1389-4420 SN - 1573-2924 VL - 19 IS - 1 SP - 39 EP - 70 ER - TY - CHAP A1 - Jekosch, Simon A1 - Sarradj, Ennes A1 - Herold, Gert A1 - Geyer, Thomas T1 - Comparison of different solvers for general inverse beamforming algorithms for highresolution aeroacoustic source characterization T2 - 7th Berlin Beamforming Conference, BeBeC Y1 - 2018 UR - http://www.bebec.eu/Downloads/BeBeC2018/Papers/BeBeC-2018-D08.pdf ER - TY - CHAP A1 - Kisler, Roman A1 - Materne, Daniel A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Modularer Versuchsstand zur Charakterisierung von Plattenschalldämpfern T2 - Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung für Akustik, 19.-22. März 2018 in München Y1 - 2018 UR - https://www-docs.b-tu.de/fg-akustik/public/veroeffentlichungen/kisler_versuchsstand_daga2018.pdf SP - 441 EP - 444 PB - Deutsche Gesellschaft für Akustik CY - Berlin ER - TY - CHAP A1 - Schneehagen, Erik W. A1 - Sarradj, Ennes A1 - Geyer, Thomas T1 - Numerische Simulation des Strömungsgeräusches eines wandbündigen Zylinders T2 - Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung für Akustik, 19.-22. März 2018 in München Y1 - 2018 UR - https://www-docs.b-tu.de/fg-akustik/public/veroeffentlichungen/schneehagen_zylinder_daga2018.pdf SP - 1001 EP - 1004 PB - Deutsche Gesellschaft für Akustik CY - Berlin ER - TY - CHAP A1 - Sarradj, Ennes A1 - Herold, Gert A1 - Geyer, Thomas T1 - Vergleich verschiedener Mikrofonarray-Verfahren anhand synthetischer Daten T2 - Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung für Akustik, 19.-22. März 2018 in München Y1 - 2018 UR - https://www-docs.b-tu.de/fg-akustik/public/veroeffentlichungen/sarradj_mikrofonarrayverfahren_daga2018.pdf SP - 1391 EP - 1394 PB - Deutsche Gesellschaft für Akustik CY - Berlin ER - TY - CHAP A1 - Geyer, Thomas A1 - Moreau, Danielle J. A1 - Sarradj, Ennes A1 - Doolan, Con T1 - Zur Schallentstehung an dreidimensionalen wandgebundenen Tragflügelprofilen T2 - Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung für Akustik, 19.-22. März 2018 in München Y1 - 2018 UR - https://www-docs.b-tu.de/fg-akustik/public/veroeffentlichungen/geyer_wandgebundeneprofile_daga2018.pdf SP - 1587 EP - 1590 PB - Deutsche Gesellschaft für Akustik CY - Berlin ER - TY - CHAP A1 - Sharma, Sparsh A1 - Sarradj, Ennes A1 - Schmidt, Heiko T1 - Low-Fidelity Stochastic Approach for Airfoil-Turbulence Interaction Noise T2 - Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung für Akustik, 19.-22. März 2018 in München Y1 - 2018 UR - https://www-docs.b-tu.de/fg-akustik/public/veroeffentlichungen/sharma_stochastic_daga2018.pdf SP - 1184 EP - 1187 PB - Deutsche Gesellschaft für Akustik CY - Berlin ER - TY - CHAP A1 - Henke, Anna-Sophia A1 - Noack, Martin A1 - Sarradj, Ennes T1 - Untersuchung des Modalverhaltens strukturierter Bleche T2 - Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung für Akustik, 19.-22. März 2018 in München Y1 - 2018 UR - https://www-docs.b-tu.de/fg-akustik/public/veroeffentlichungen/henke_modalverhalten_daga2018.pdf SP - 469 EP - 472 PB - Deutsche Gesellschaft für Akustik CY - Berlin ER - TY - GEN A1 - Kisler, Roman A1 - Sarradj, Ennes T1 - Plate Silencers for Broadband Low Frequency Sound Attenuation T2 - Acta Acustica united with Acustica N2 - An efficiency improvement for the implementation of a semi-analytical model of plate silencers in ducts is presented in this work. It is shown that a high approximation quality can be maintained even if the computation effort is reduced significantly. Thus, preliminary designs of plate silencers for specific purposes can be conducted with little effort. In addition, the accelerated implementation is utilized to perform an extensive parameter variation in order to find a best case configuration of silen properties and corresponding design rules. The results of these studies show that a tuning of plate and geometry parameters allow for substantial increases in a silencer's attenuation performance. Y1 - 2018 SN - 1610-1928 SN - 1861-9959 VL - 104 IS - 3 SP - 521 EP - 527 ER - TY - GEN A1 - Moreau, Danielle J. A1 - Geyer, Thomas A1 - Doolan, Con A1 - Sarradj, Ennes T1 - Surface curvature effects on the tonal noise of a wall-mounted finite airfoil T2 - The Journal of the Acoustical Society of America N2 - This paper is concerned with the influence of camber on the noise of a wall-mounted finite airfoil with natural boundary layer transition. Tonal noise measurements taken in an aeroacoustic wind tunnel are presented for airfoils with aspect ratio of 2, NACAxx12 profile and camber between 0 and 6% at 40% chord. The results show camber is an important parameter that determines the operating conditions for which acoustic tone generation occurs and the number and intensity of the tones produced. Airfoils with 0%–2% camber have an acoustic signature that is dominated by a high amplitude primary tone, whereas the spectra of airfoils with higher camber of 4%–6% feature a more pronounced side tone structure. Tonal noise production does not collapse with lift coefficient, demonstrating that the local flow conditions influence the noise source. Tonal noise production is explained in terms of changes to mean flow topology, namely the location of flow separation, which is linked to tonal noise generation. Scaling of airfoil tonal noise is found to vary with angle of attack and pressure gradient. Empirical scaling laws for the primary tone frequency dependence on velocity are also derived for the cambered airfoils. Y1 - 2018 U6 - https://doi.org/10.1121/1.5040981 SN - 1520-8524 VL - 143 IS - 6 SP - 3460 EP - 3473 ER - TY - GEN A1 - Geyer, Thomas A1 - Moreau, Danielle J. A1 - Giesler, Jens A1 - Hall, Philipp A1 - Sarradj, Ennes A1 - Doolan, Con T1 - Measurement of the noise generated by wall-mounted airfoils of different thickness T2 - 24th AIAA/CEAS Aeroacoustics Conference 2018, Atlanta, USA, 25 June - 29 June 2018, (AIAA 2018-3796) Y1 - 2018 UR - https://arc.aiaa.org/doi/abs/10.2514/6.2018-3796 SN - 978-1-62410-560-9 PB - AIAA CY - Reston, Va ER - TY - GEN A1 - Geyer, Thomas A1 - Sharma, Sparsh A1 - Sarradj, Ennes T1 - Detached Eddy Simulation of the Flow Noise Generation of Cylinders with Porous Cover T2 - 24th AIAA/CEAS Aeroacoustics Conference 2018, Atlanta, USA, 25 June - 29 June 2018, (AIAA 2018-3472) Y1 - 2018 UR - https://arc.aiaa.org/doi/abs/10.2514/6.2018-3472 SN - 978-1-62410-560-9 PB - AIAA CY - Reston, Va ER - TY - GEN A1 - Çaldichoury, Iñaki A1 - Souli, Mhamed A1 - Sarradj, Ennes A1 - Geyer, Thomas A1 - Del Pin, Facundo T1 - Numerical investigation of flow around hairy flaps cylinder using FSI Capabilities T2 - The International journal of multiphysics Y1 - 2018 SN - 2048-3961 SN - 1750-9548 VL - 12 IS - 2 SP - 189 EP - 208 ER - TY - CHAP A1 - Sharma, Sparsh A1 - Sarradj, Ennes T1 - Fluctuating inflow conditions for time-domain boundary element method for airfoil-turbulence interaction noise T2 - Proceedings of the 15th International Symposium on Unsteady Aerodynamics, Aeroacoustics & Aeroelasticity of Turbomachines ISUAAAT15, 24-27 September 2018, University of Oxford, UK Y1 - 2018 UR - https://www-docs.b-tu.de/fg-akustik/public/veroeffentlichungen/sharma_turbulence_ISUAAAT2018.pdf PB - ISUAAAT Scientific Committee ER - TY - CHAP A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Noise reduction and aerodynamics of airfoils with porous trailing edges T2 - INTER-NOISE 2018, the 47th International Congress and Exposition on Noise Control Engineering, Chicago, Illinois, USA Y1 - 2018 UR - https://www-docs.b-tu.de/fg-akustik/public/veroeffentlichungen/geyer_porousTE_internoise2018.pdf ER - TY - CHAP A1 - Sharma, Sparsh A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Time Domain Boundary Element Method for the Leading-Edge Noise subjected to Linear Vorticity T2 - INTER-NOISE 2018, the 47th International Congress and Exposition on Noise Control Engineering, Chicago, Illinois, USA Y1 - 2018 UR - https://www-docs.b-tu.de/fg-akustik/public/veroeffentlichungen/sharma_bem_internoise2018.pdf ER - TY - GEN A1 - Geyer, Thomas A1 - Lucius, Andreas A1 - Schrödter, Marcus A1 - Schneider, Marc A1 - Sarradj, Ennes T1 - Reduction of Turbulence Interaction Noise Through Airfoils With Perforated Leading Edges T2 - Acta Acustica united with Acustica Y1 - 2019 U6 - https://doi.org/10.3813/AAA.919292 SN - 1610-1928 SN - 1436-7947 VL - 105 IS - 1 SP - 109 EP - 122 ER - TY - GEN A1 - Geyer, Thomas A1 - Kamps, Laura A1 - Sarradj, Ennes A1 - Brücker, Christoph T1 - Vortex Shedding and Modal Behavior of a Circular Cylinder Equipped with Flexible Flaps T2 - Acta Acustica united with Acustica Y1 - 2019 U6 - https://doi.org/10.3813/aaa.919301 SN - 1610-1928 SN - 1436-7947 VL - 105 IS - 1 SP - 210 EP - 219 ER - TY - GEN A1 - Sharma, Sparsh A1 - Sarradj, Ennes T1 - Two-dimensional isotropic turbulent inflow conditions for vortex particle method T2 - Physical Review Fluids Y1 - 2019 U6 - https://doi.org/10.1103/PhysRevFluids.4.022701 SN - 2469-990X VL - 4 IS - 2 ER - TY - GEN A1 - Henke, Anna-Sophia A1 - Noack, Martin A1 - Geyer, Thomas A1 - Heinrich, Christoph Rocky A1 - Beirow, Bernd A1 - Sarradj, Ennes A1 - Kühhorn, Arnold T1 - Calculation of the Modal Behavior of Structured Sheet Metal T2 - International Journal of Lightweight Materials and Manufacture Y1 - 2019 U6 - https://doi.org/10.1016/j.ijlmm.2019.01.004 SN - 2588-8404 ER - TY - GEN A1 - Henke, Anna-Sophia A1 - Tepe, Ali A1 - Sarradj, Ennes T1 - Untersuchung des Abstrahlverhaltens strukturierter Bleche T2 - Fortschritte der Akustik - DAGA 2019, 45. Jahrestagung für Akustik, 18.-21. März 2019 in Rostock N2 - Stahlbleche sind auf Grund ihrer einfachen Fertigung und vielfältigen Anwendungsmöglichkeiten unentbehrlich in Bereichen wie dem Maschinen- und Fahrzeugbau oder der Architektur. Durch das Einbringen von Strukturen kann die Steifigkeit von Stahlplatten erhöht werden. So kann bei einem geringeren Materialeinsatz gleichbleibenden statischen Ansprüchen genügt werden. Eine derartige Umformung führt jedoch auch zu einem veränderten akustischen Verhalten von strukturierten Blechen gegenüber glatten Blechen. Im Rahmen einer Studie an der BTU Cottbus-Senftenberg zum akustischen Verhalten hexagonal wabenstrukturierter Stahlbleche wurde das Abstrahlverhalten dieser Bleche untersucht. Dazu wurden im Fensterprüfstand der TU Berlin experimentell die abgestrahlte Schallleistung sowie die Schwingschnelle von mit einem Shaker angeregten Blechen ermittelt. Aus den so gewonnenen Daten wurde das Abstrahlmaß berechnet. Der Beitrag zeigt das Verfahren und veranschaulicht die Ergebnisse vergleichend für glatte und hexagonal strukturierte Bleche. Dabei wird im Besonderen auf den Einfluss der Strukturierung auf das Abstrahlmaß der Stahlbleche eingegangen. Y1 - 2019 UR - https://www.dega-akustik.de/publikationen/tagungsbaende/verzeichnisse/ ER - TY - GEN A1 - Merino-Martinez, Roberto A1 - Sijtsma, Pieter A1 - Snellen, Mirjam A1 - Ahlefeldt, Thomas A1 - Antoni, Jerome A1 - Bahr, Christopher A1 - Blacodon, Daniel A1 - Ernst, Daniel A1 - Finez, Arthur A1 - Funke, Stefan A1 - Geyer, Thomas A1 - Haxter, Stefan A1 - Herold, Gert A1 - Huang, Xun A1 - Humphreys, William A1 - Leclère, Quentin A1 - Malgoezar, Anwar A1 - Michel, Ulf A1 - Padois, Thomas A1 - Pereira, Antonio A1 - Picard, Christophe A1 - Sarradj, Ennes A1 - Siller, Henri A1 - Simons, Dick A1 - Spehr, Carsten T1 - A review of acoustic imaging methods using phased microphone arrays T2 - CEAS Aeronautical Journal N2 - Phased microphone arrays have become a well-established tool for performing aeroacoustic measurements in wind tunnels (both open-jet and closed-section), flying aircraft, and engine test beds. This paper provides a review of the most well-known and state-of-the-art acoustic imaging methods and recommendations on when to use them. Several exemplary results showing the performance of most methods in aeroacoustic applications are included. This manuscript provides a general introduction to aeroacoustic measurements for non-experienced microphone-array users as well as a broad overview for general aeroacoustic experts. Y1 - 2019 U6 - https://doi.org/10.1007/s13272-019-00383-4 SN - 1869-5582 SN - 1869-5590 VL - 10 IS - 1 SP - 197 EP - 230 ER - TY - GEN A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Self Noise Reduction and Aerodynamics of Airfoils With Porous Trailing Edges T2 - Acoustics Y1 - 2019 U6 - https://doi.org/10.3390/acoustics1020022 SN - 2624-599X VL - 1 IS - 2 SP - 393 EP - 409 ER - TY - GEN A1 - Sharma, Sparsh A1 - Geyer, Thomas A1 - Sarradj, Ennes A1 - Schmidt, Heiko T1 - Numerical investigation of noise generation by rod-airfoil configuration using DES (SU2) and the FW-H analogy T2 - 25th AIAA/CEAS Aeroacoustics Conference 2019, Delft, The Netherlands, 20 - 24 May 2019, (AIAA 2019-2400) KW - airfoil noise KW - computational aeroacoustics KW - cylinder noise KW - detached eddy simulatio KW - ffowcs-williams hawkings KW - rod-airfoil Y1 - 2019 UR - https://arc.aiaa.org/doi/10.2514/6.2019-2400 U6 - https://doi.org/10.2514/6.2019-2400 SP - 1 EP - 17 ER - TY - CHAP A1 - Moreau, Danielle J. A1 - Geyer, Thomas A1 - Doolan, Con A1 - Sarradj, Ennes ED - Zhou, Yu ED - Kimura, Motoaki ED - Peng, Guoyi ED - Lucey, A. D. ED - Huang, Lixi T1 - Influence of Camber on Wall-Mounted Finite Airfoil Tonal Noise Generation T2 - Fluid-Structure-Sound Interactions and Control Proceedings of the 4th Symposium on Fluid-Structure-Sound Interactions and Control Y1 - 2019 SN - 978-981-10-7541-4 SN - 978-981-10-7542-1 U6 - https://doi.org/10.1007/978-981-10-7542-1_51 SP - 337 EP - 342 PB - Springer CY - Singapore ER - TY - GEN A1 - Geyer, Thomas A1 - Wasala, Sahan A1 - Sarradj, Ennes T1 - Experimental Study of Airfoil Leading Edge Combs for Turbulence Interaction Noise Reduction T2 - Acoustics Y1 - 2020 U6 - https://doi.org/10.3390/acoustics2020014 SN - 2624-599X VL - 2 IS - 2 SP - 207 EP - 223 ER - TY - GEN A1 - Sharma, Sparsh A1 - Sarradj, Ennes A1 - Schmidt, Heiko T1 - Stochastic modelling of leading-edge noise in time-domain using vortex particles T2 - Journal of Sound and Vibration Y1 - 2020 U6 - https://doi.org/10.1016/j.jsv.2020.115656 SN - 0022-460X VL - Vol. 488 ER - TY - GEN A1 - Ayton, Lorna A1 - Colbrook, Matthew A1 - Geyer, Thomas A1 - Chaitanya, Paruchuri A1 - Sarradj, Ennes T1 - Reducing aerofoil–turbulence interaction noise through chordwise-varying porosity T2 - Journal of Fluid Mechanics Y1 - 2020 U6 - https://doi.org/10.1017/jfm.2020.746 SN - 1469-7645 VL - 906 SP - A1 EP - A28 ER - TY - GEN A1 - Sharma, Sparsh A1 - Klein, Marten A1 - Schmidt, Heiko A1 - Sarradj, Ennes T1 - On a lower-order framework for jet noise prediction based on one-dimensional turbulence T2 - arXiv N2 - Noise prediction requires the resolution of relevant acoustic sources on all scales of a turbulent flow. High-resolution direct numerical and large-eddy simulation would be ideal but both are usually too costly despite developments in high performance computing. Lower-order modeling approaches are therefore of general interest. A crucial but standing problem for accurate predictive modeling is the estimation of missing noise from the modeled scales. In this paper we address this problem by presenting a novel lower-order framework that couples the one-dimensional turbulence model to the Ffowcs-Williams and Hawkings approach for prediction of the far-field noise of a subsonic turbulent round jet. KW - Ffowcs-Williams and Hawkings equation KW - jet noise KW - one-dimensional turbulence KW - turbulent mixing noise Y1 - 2020 UR - https://arxiv.org/abs/2010.11050 SP - 1 EP - 4 ER - TY - GEN A1 - Schneehagen, Erik W. A1 - Geyer, Thomas A1 - Sarradj, Ennes A1 - Moreau, Danielle J. T1 - Aeroacoustic noise reduction by application of end plates on wall‑mounted finite airfoils T2 - Experiments in Fluids Y1 - 2021 U6 - https://doi.org/10.1007/s00348-021-03204-9 SN - 0723-4864 SN - 1432-1114 VL - 62 IS - 5 ER - TY - GEN A1 - Geyer, Thomas A1 - Fritzsche, Christoph A1 - Sarradj, Ennes A1 - Wagner, Hermann T1 - Der leise Flug der Eule T2 - Akustik Journal Y1 - 2021 UR - https://www.dega-akustik.de/fileadmin/dega-akustik.de/publikationen/akustik-journal/21-02/akustik_journal_2021_02_online.pdf VL - 2021 IS - 2 SP - 9 EP - 17 ER - TY - GEN A1 - Ayton, Lorna A1 - Colbrook, Matthew A1 - Geyer, Thomas A1 - Chaitanya, Paruchuri A1 - Sarradj, Ennes T1 - Modelling chordwise-varying porosity to reduce aerofoil-turbulence interaction noise T2 - 27th AIAA/CEAS Aeroacoustics Conference 2021, Virtual Event, August 2 - 6 2021 Y1 - 2021 U6 - https://doi.org/10.2514/6.2021-2190 ER - TY - GEN A1 - Sharma, Sparsh A1 - Geyer, Thomas A1 - Sarradj, Ennes A1 - Schmidt, Heiko T1 - Experimental validation of a lower-order model for leading-edge noise based on vortex method T2 - 27th AIAA/CEAS Aeroacoustics Conference 2021, Virtual Event, August 2 - 6 2021 Y1 - 2021 U6 - https://doi.org/10.2514/6.2021-2250 ER - TY - GEN A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Aerodynamische Schallentstehung durchströmter Netze T2 - Fortschritte der Akustik - DAGA, 48. Jahrestagung für Akustik, 21. - 24. März 2022 Y1 - 2022 UR - https://pub.dega-akustik.de/DAGA_2022/data/articles/000133.pdf UR - https://www.daga2022.de/programm SP - 109 ER - TY - GEN A1 - Schneehagen, Erik W. A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Reduzierung des Eigengeräuschs von Tragflügeln durch Seitenplatten T2 - Fortschritte der Akustik - DAGA, 48. Jahrestagung für Akustik Y1 - 2022 UR - https://pub.dega-akustik.de/DAGA_2022/data/articles/000189.pdf ER - TY - GEN A1 - Schneehagen, Erik W. A1 - Geyer, Thomas A1 - Sarradj, Ennes T1 - Influence of end plate placement on the reduction of airfoil tip vortex formation noise T2 - Acta Acustica Y1 - 2022 UR - https://acta-acustica.edpsciences.org/articles/aacus/full_html/2022/01/aacus220025/aacus220025.html U6 - https://doi.org/10.1051/aacus/2022053 SN - 2681-4617 VL - 6 SP - 1 EP - 14 ER - TY - GEN A1 - Neubauer, Moritz A1 - Genßler, Julia A1 - Radmann, Vincent A1 - Kohlenberg, Fleming A1 - Pohl, Michael A1 - Böhme, Kurt A1 - Knobloch, Karsten A1 - Sarradj, Ennes A1 - Höschler, Klaus A1 - Modler, Niels A1 - Enghardt, Lars T1 - Experimental and Numerical Investigation of Novel Acoustic Liners and Their Design for Aero-Engine Applications T2 - Aerospace N2 - This paper presents a combined experimental and numerical investigation on a novel liner concept for enhanced low-frequency and broadband acoustic attenuation. In particular, two different realizations, derived from conventional Helmholtz resonators (HR) and plate resonators (PR) are investigated, which both deploy flexible materials with material inherent damping. In this context, a comprehensive experimental investigation was carried out focusing the identification and evaluation of various geometric parameters and material properties on the acoustics dissipation and related properties of various materials in a simplified setup of a single Helmholtz resonator with flexible walls (FHR concept). Furthermore, a parameter study based on analytical models was performed for both liner concepts, taking into account material as well as geometric parameters and their effects on transmission loss. In addition, design concepts that enable cylindrical or otherwise curved liner structures and the corresponding manufacturing technologies are presented, while considering essential structural features such as drainage. With respect to the potential application in jet engines, a structural–mechanical analysis considering the relevant load cases to compare and discuss the mechanical performance of a classical HR and the FHR concept liner is presented. Finally, both concepts are evaluated and possible challenges and potentials for further implementation are described. Y1 - 2023 U6 - https://doi.org/10.3390/aerospace10010005 SN - 2226-4310 VL - 10 IS - 1 ER - TY - GEN A1 - Geyer, Thomas A1 - Windisch, Thomas A1 - Fritzsche, Christoph A1 - Sarradj, Ennes T1 - Dataset on permeability of wings from owls and non-silently flying birds T2 - Data in Brief Y1 - 2024 U6 - https://doi.org/10.1016/j.dib.2023.109825 SN - 2352-3409 VL - 52 ER - TY - GEN A1 - Geyer, Thomas A1 - Windisch, Thomas A1 - Fritzsche, Christoph A1 - Sarradj, Ennes T1 - Dataset on airflow resistance of wings from owls and non-silently flying birds Y1 - 2023 U6 - https://doi.org/10.17632/ndcndtstcf.1 ER -