TY - GEN A1 - Geyer, Thomas A1 - Sarradj, Ennes A1 - Herold, Gert T1 - Flow Noise Generation of Cylinders with Soft Porous Cover T2 - 21st AIAA/CEAS Aeroacoustics Conference 2015, Dallas, Texas, USA, 22 - 26 June 2015, held at the AIAA Aviation Forum 2015, vol. 5, (AIAA 2015-3147) Y1 - 2015 SN - 978-1-5108-0820-1 SP - 3695 EP - 3711 PB - Curran CY - Red Hook, NY ER - TY - CHAP A1 - Geyer, Thomas A1 - Sarradj, Ennes A1 - Rex, Christoph A1 - Kießling, Sebastian A1 - Neefe, Alexander T1 - Messung der Schallcharakteristik einer Mikrogasturbine T2 - Fortschritte der Akustik, DAGA 2015, Nürnberg, 41. Jahrestagung für Akustik, 16. - 19. März 2015 Y1 - 2015 SN - 978-3-939296-08-9 PB - Deutsche Gesellschaft für Akustik e.V. CY - Berlin ER - TY - CHAP A1 - Henke, Anna-Sophia A1 - Sarradj, Ennes T1 - Körperschallverhalten strukturierter Bleche T2 - Fortschritte der Akustik, DAGA 2015, Nürnberg, 41. Jahrestagung für Akustik, 16. - 19. März 2015 Y1 - 2015 SN - 978-3-939296-08-9 PB - Deutsche Gesellschaft für Akustik e.V. CY - Berlin ER - TY - CHAP A1 - Herold, Gert A1 - Sarradj, Ennes T1 - Microphone Array Method for the Characterization of Rotating Sound Sources in Axial Fans T2 - Fan 2015, International Conference on Fan Noise, Technology and Numerical Methods, Lyon 2015 Y1 - 2015 SN - 978-0-9572374-3-8 PB - Institution of Mechanical Engineers CY - London ER - TY - GEN A1 - Herold, Gert A1 - Sarradj, Ennes T1 - An Approach to Estimate the Reliability of Microphone Array Methods T2 - 21st AIAA/CEAS Aeroacoustics Conference 2015, Dallas, Texas, USA, 22 - 26 June 2015, held at the AIAA Aviation Forum 2015, vol. 4, (AIAA 2015-2977) Y1 - 2015 SN - 978-1-5108-0820-1 SP - 2688 EP - 2697 PB - Curran CY - Red Hook, NY ER - TY - CHAP A1 - Herold, Gert A1 - Sarradj, Ennes T1 - Mikrofonarrayverfahren zur Messung der abgestrahlten Schallleistung von Motorkomponenten T2 - Fortschritte der Akustik, DAGA 2015, Nürnberg, 41. Jahrestagung für Akustik, 16. - 19. März 2015 Y1 - 2015 SN - 978-3-939296-08-9 PB - Deutsche Gesellschaft für Akustik e.V. CY - Berlin ER - TY - CHAP A1 - Sarradj, Ennes T1 - Optimal Planar Microphone Array Arrangements T2 - Fortschritte der Akustik, DAGA 2015, Nürnberg, 41. Jahrestagung für Akustik, 16. - 19. März 2015 Y1 - 2015 SN - 978-3-939296-08-9 PB - Deutsche Gesellschaft für Akustik e.V. CY - Berlin ER - TY - GEN A1 - Geyer, Thomas A1 - Sarradj, Ennes A1 - Rex, Christoph A1 - Kießling, Sebastian A1 - Neefe, Alexander T1 - Schallemission einer Mikrogasturbine T2 - Lärmbekämpfung Y1 - 2015 SN - 1436-4999 IS - 6 SP - 268 EP - 272 ER - 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 -