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 - GEN A1 - Geyer, Thomas A1 - Moreau, Danielle J. A1 - Zhang, Tingyi A1 - Schneehagen, Erik W. A1 - Ding, Yuchen T1 - Experimental investigation of novel, low-noise turbine blade tip designs T2 - Fortschritte der Akustik - DAGA, 46. Jahrestagung für Akustik, 16.-19. März 2020 in Hannover Y1 - 2020 UR - https://www-docs.b-tu.de/fg-akustik/public/veroeffentlichungen/geyer_noveltip_daga2020.pdf 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 - 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 - Geyer, Thomas A1 - Schneehagen, Erik W. A1 - Herold, Gert A1 - Zhang, Tingyi A1 - Moreau, Danielle J. T1 - Reduction of rotor aerodynamic noise using porous blade tips T2 - Fortschritte der Akustik - DAGA, 50. Jahrestagung für Akustik N2 - Motivated by promising results from experiments on the noise reduction performance of finite wall-mounted airfoils with a porous tip in an aeroacoustic wind tunnel, corresponding measurements were performed in a dedicated rotor test rig. This rig features a 3 kW direct-drive electric motor with three rotor blades of 1.1 m diameter. In the experiments, a variety of different tip modifications was tested regarding their noise reducing performance, including different porous materials that were manufactured using rapid prototyping. Acoustic measurements were performed at different rotationals speeds and blade angles using a ring-shaped microphone array consisting of 60 evenly spaced microphones. The rotational speed was measured using a laser sensor. Different beamforming algorithms were used in post-processing to help analyzing the data. The results show that porous tips can lead to a notable noise reduction at low frequencies, but a small penalty at medium and high frequencies which may be due to the surface roughness of the porous tips. This trend seems more severe for lower blade angles than for higher ones. These findings agree well with those obtained from the previous wind tunnel measurements. Y1 - 2024 UR - https://pub.dega-akustik.de/DAGA_2024/konferenz?article=471 ER -