@misc{GeyerSchulzThuermeretal., author = {Geyer, Thomas and Schulz, Adrian and Th{\"u}rmer, Konrad and Sarradj, Ennes and Stapel, Jennifer}, title = {Schallemission wasserwirtschaftlicher Anlagen}, series = {L{\"a}rmbek{\"a}mpfung}, journal = {L{\"a}rmbek{\"a}mpfung}, number = {3}, issn = {1436-4999}, pages = {99 -- 103}, language = {de} } @inproceedings{MoreauGeyerDoolanetal., author = {Moreau, Danielle J. and Geyer, Thomas and Doolan, Con and Sarradj, Ennes}, title = {Influence of Camber on Wall-Mounted Finite Airfoil Tonal Noise Generation}, series = {4th Symposium on Fluid-Structure-Sound Interactions and Control, Tokio, 2017}, booktitle = {4th Symposium on Fluid-Structure-Sound Interactions and Control, Tokio, 2017}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-10-7542-1}, pages = {337 -- 342}, language = {en} } @misc{GeyerPoppeSarradj, author = {Geyer, Thomas and Poppe, Willi and Sarradj, Ennes}, title = {Measurement of flow noise generation and pressure loss of nets and screens}, series = {Applied Acoustics}, volume = {134}, journal = {Applied Acoustics}, issn = {0003-682X}, doi = {10.1016/j.apacoust.2018.01.008}, pages = {69 -- 74}, language = {en} } @misc{HenkeSarradjLanghof, author = {Henke, Anna-Sophia and Sarradj, Ennes and Langhof, Carsten}, title = {Driving-point mobility and sound insulation of structured sheet metal}, series = {Applied Acoustics}, volume = {136}, journal = {Applied Acoustics}, issn = {0003-682X}, pages = {113 -- 122}, language = {en} } @misc{HoeltgenBreussHeroldetal., author = {Hoeltgen, Laurent and Breuß, Michael and Herold, Gert and Sarradj, Ennes}, title = {Sparse ℓ1 regularisation of matrix valued models for acoustic source characterisation}, series = {Optimization and Engineering}, volume = {19}, journal = {Optimization and Engineering}, number = {1}, issn = {1389-4420}, doi = {10.1007/s11081-017-9357-2}, pages = {39 -- 70}, abstract = {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.}, language = {en} } @inproceedings{JekoschSarradjHeroldetal., author = {Jekosch, Simon and Sarradj, Ennes and Herold, Gert and Geyer, Thomas}, title = {Comparison of different solvers for general inverse beamforming algorithms for highresolution aeroacoustic source characterization}, series = {7th Berlin Beamforming Conference, BeBeC}, booktitle = {7th Berlin Beamforming Conference, BeBeC}, pages = {10}, language = {en} } @inproceedings{KislerMaterneGeyeretal., author = {Kisler, Roman and Materne, Daniel and Geyer, Thomas and Sarradj, Ennes}, title = {Modularer Versuchsstand zur Charakterisierung von Plattenschalld{\"a}mpfern}, series = {Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung f{\"u}r Akustik, 19.-22. M{\"a}rz 2018 in M{\"u}nchen}, booktitle = {Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung f{\"u}r Akustik, 19.-22. M{\"a}rz 2018 in M{\"u}nchen}, publisher = {Deutsche Gesellschaft f{\"u}r Akustik}, address = {Berlin}, pages = {441 -- 444}, language = {de} } @inproceedings{SchneehagenSarradjGeyer, author = {Schneehagen, Erik W. and Sarradj, Ennes and Geyer, Thomas}, title = {Numerische Simulation des Str{\"o}mungsger{\"a}usches eines wandb{\"u}ndigen Zylinders}, series = {Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung f{\"u}r Akustik, 19.-22. M{\"a}rz 2018 in M{\"u}nchen}, booktitle = {Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung f{\"u}r Akustik, 19.-22. M{\"a}rz 2018 in M{\"u}nchen}, publisher = {Deutsche Gesellschaft f{\"u}r Akustik}, address = {Berlin}, pages = {1001 -- 1004}, language = {de} } @inproceedings{SarradjHeroldGeyer, author = {Sarradj, Ennes and Herold, Gert and Geyer, Thomas}, title = {Vergleich verschiedener Mikrofonarray-Verfahren anhand synthetischer Daten}, series = {Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung f{\"u}r Akustik, 19.-22. M{\"a}rz 2018 in M{\"u}nchen}, booktitle = {Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung f{\"u}r Akustik, 19.-22. M{\"a}rz 2018 in M{\"u}nchen}, publisher = {Deutsche Gesellschaft f{\"u}r Akustik}, address = {Berlin}, pages = {1391 -- 1394}, language = {de} } @inproceedings{GeyerMoreauSarradjetal., author = {Geyer, Thomas and Moreau, Danielle J. and Sarradj, Ennes and Doolan, Con}, title = {Zur Schallentstehung an dreidimensionalen wandgebundenen Tragfl{\"u}gelprofilen}, series = {Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung f{\"u}r Akustik, 19.-22. M{\"a}rz 2018 in M{\"u}nchen}, booktitle = {Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung f{\"u}r Akustik, 19.-22. M{\"a}rz 2018 in M{\"u}nchen}, publisher = {Deutsche Gesellschaft f{\"u}r Akustik}, address = {Berlin}, pages = {1587 -- 1590}, language = {de} } @inproceedings{SharmaSarradjSchmidt, author = {Sharma, Sparsh and Sarradj, Ennes and Schmidt, Heiko}, title = {Low-Fidelity Stochastic Approach for Airfoil-Turbulence Interaction Noise}, series = {Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung f{\"u}r Akustik, 19.-22. M{\"a}rz 2018 in M{\"u}nchen}, booktitle = {Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung f{\"u}r Akustik, 19.-22. M{\"a}rz 2018 in M{\"u}nchen}, publisher = {Deutsche Gesellschaft f{\"u}r Akustik}, address = {Berlin}, pages = {1184 -- 1187}, language = {en} } @inproceedings{HenkeNoackSarradj, author = {Henke, Anna-Sophia and Noack, Martin and Sarradj, Ennes}, title = {Untersuchung des Modalverhaltens strukturierter Bleche}, series = {Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung f{\"u}r Akustik, 19.-22. M{\"a}rz 2018 in M{\"u}nchen}, booktitle = {Fortschritte der Akustik - DAGA 2018, 44. Jahrestagung f{\"u}r Akustik, 19.-22. M{\"a}rz 2018 in M{\"u}nchen}, publisher = {Deutsche Gesellschaft f{\"u}r Akustik}, address = {Berlin}, pages = {469 -- 472}, language = {de} } @misc{KislerSarradj, author = {Kisler, Roman and Sarradj, Ennes}, title = {Plate Silencers for Broadband Low Frequency Sound Attenuation}, series = {Acta Acustica united with Acustica}, volume = {104}, journal = {Acta Acustica united with Acustica}, number = {3}, issn = {1610-1928}, pages = {521 -- 527}, abstract = {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.}, language = {en} } @misc{MoreauGeyerDoolanetal., author = {Moreau, Danielle J. and Geyer, Thomas and Doolan, Con and Sarradj, Ennes}, title = {Surface curvature effects on the tonal noise of a wall-mounted finite airfoil}, series = {The Journal of the Acoustical Society of America}, volume = {143}, journal = {The Journal of the Acoustical Society of America}, number = {6}, issn = {1520-8524}, doi = {10.1121/1.5040981}, pages = {3460 -- 3473}, abstract = {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.}, language = {en} }