@inproceedings{RetkaHawkingsMarburg, author = {Retka, Stefanie and Hawkings, Stuart C. and Marburg, Steffen}, title = {Acoustic Radiation Problem of a Recorder Fluid}, series = {Proceedings of the 9th International Conference on Theoretical and Computational Acoustics, Dresden}, booktitle = {Proceedings of the 9th International Conference on Theoretical and Computational Acoustics, Dresden}, editor = {Marburg, Steffen}, pages = {129 -- 134}, language = {en} } @inproceedings{RetkaMarburg, author = {Retka, Stefanie and Marburg, Steffen}, title = {Modal Analysis of a Fluid inside and around a Recorder}, series = {Proceedings of NAG/DAGA 2009, International Conference on Acoustics, Rotterdam}, booktitle = {Proceedings of NAG/DAGA 2009, International Conference on Acoustics, Rotterdam}, editor = {Boone, M. M.}, pages = {228 -- 229}, language = {en} } @inproceedings{RetkaHervellaNietoMarburg, author = {Retka, Stefanie and Hervella-Nieto, Luis and Marburg, Steffen}, title = {Vergleich der akustischen Finite-Elemente-L{\"o}sungen zu Eigenwertproblem und Quellproblem mit Raviart-Thomas- sowie Lagrange-Elementen}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 34. Jahrestagung f{\"u}r Akustik, Dresden}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 34. Jahrestagung f{\"u}r Akustik, Dresden}, editor = {Jekosch, U. and Hoffmann, R.}, pages = {79 -- 80}, language = {de} } @inproceedings{Retka, author = {Retka, Stefanie}, title = {A strategy to implement volume sources into Galbrun equation}, series = {PAMM - Proceedings in Applied Mathematics and Mechanics}, volume = {16}, booktitle = {PAMM - Proceedings in Applied Mathematics and Mechanics}, number = {1}, doi = {10.1002/pamm.201610300}, pages = {623 -- 624}, abstract = {When considering noise propagation in flow in frequency domain computations, the standard Helmholtz equation is not sufficient to describe these effects. Therefore, using the linearized Euler equations (LEE) is common practice to describe sound propagation based on displacement perturbation. Galbrun reformulated the LEE in terms of an arbitrary Eulerian-Lagrangian description, which resulted in the displacement based Galbrun equation. This equation can also be formulated in terms of pressure and displacements. We want to include sources (monopoles, dipoles and quadrupoles) in the harmonic analysis of Galbrun equation when a volume flow is present. In a first step we will solve Galbrun equation considering a volume flow. The velocity field is obtained in a CFD computation. Afterwards, the sources will be included in the acoustic computations as well. Preliminary computational results are discussed and implications for future directions of research are addressed.}, language = {en} } @article{RetkaHervellaNietoMarburg, author = {Retka, Stefanie and Hervella-Nieto, Luis and Marburg, Steffen}, title = {Comparison of pressure and displacement formulations for finite elements in linear time-harmonic acoustics}, series = {Computers and Structures}, journal = {Computers and Structures}, publisher = {151}, doi = {10.1016/j.compstruc.2015.01.009}, pages = {459 -- 57}, abstract = {In this article, we compare the finite element solution of the pressure and the displacement formulations for the acoustic problem in the frequency domain. The Helmholtz differential equation is solved for both, the spectral and the source problems, and each of these is formulated in terms of pressure and displacement. The pressure formulation allows to use standard Lagrangian elements whereas Raviart-Thomas elements are applied for the displacement formulation. Both formulations are tested in several examples. It is shown that Raviart-Thomas elements account for a reasonable alternative to Lagrangian elements in some cases.}, language = {en} } @inproceedings{Retka, author = {Retka, Stefanie}, title = {D{\"a}mpfungsgrade und Eigenfrequenzverhalten offener Hohlr{\"a}ume}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 41. Jahrestagung f{\"u}r Akustik, N{\"u}rnberg}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 41. Jahrestagung f{\"u}r Akustik, N{\"u}rnberg}, editor = {Becker, S.}, pages = {855 -- 857}, language = {de} } @inproceedings{Retka, author = {Retka, Stefanie}, title = {Resonanzen und D{\"a}mpfungseigenschaften offener Hohlr{\"a}ume}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 40. Jahrestagung f{\"u}r Akustik, Oldenburg}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 40. Jahrestagung f{\"u}r Akustik, Oldenburg}, editor = {Kollmeier, B. and Blau, M. and Van der Par, S.}, pages = {371 -- 372}, language = {de} } @inproceedings{RetkaMarburg, author = {Retka, Stefanie and Marburg, Steffen}, title = {Open Bottles - Helmholtz resonator and quarter wave effect}, series = {AIA-DAGA - Proceedings of the International Conference on Acoustics, Meran}, booktitle = {AIA-DAGA - Proceedings of the International Conference on Acoustics, Meran}, editor = {Peretti, A. and Scheuren, J.}, pages = {1197 -- 1198}, language = {en} } @article{RetkaMarburg, author = {Retka, Stefanie and Marburg, Steffen}, title = {An infinite element for the solution of Galbrun equation}, series = {ZAMM - Zeitschrift f{\"u}r Angewandte Mathematik und Mechanik}, volume = {93}, journal = {ZAMM - Zeitschrift f{\"u}r Angewandte Mathematik und Mechanik}, number = {2-3}, pages = {154 -- 162}, language = {en} } @phdthesis{Retka, author = {Retka, Stefanie}, title = {Numerische Umsetzung der Galbrun-Gleichung zur Modalanalyse str{\"o}mender Medien in Außenraumproblemen unter Einsatz finiter und infiniter Elemente}, url = {http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-90024}, abstract = {In der vorliegenden Arbeit wird ein Programmcode zur numerischen Modalanalyse dreidimensionaler Fluide in komplexen akustischen Systemen, speziell in Resonatoren, entwickelt. Mit diesem Code ist es m{\"o}glich, turbulente Str{\"o}mungen im Rahmen der Modalanalyse zu ber{\"u}cksichtigen. Hierzu wird ein realistisches Str{\"o}mungsprofil, ermittelt mithilfe eines 3D-Navier-Stokes-L{\"o}sers, verwendet. Der Hauptteil der Arbeit befasst sich mit der Herleitung der f{\"u}r die Berechnung notwendigen Galbrun-Gleichung und deren Aufbereitung zur numerischen Analyse. F{\"u}r die numerische Umsetzung kommt die Methode der finiten Elemente in Verbindung mit komplex konjugierten, infiniten Astley-Leis Elementen zur Anwendung. Die infiniten Elemente werden genutzt, um in den betrachteten Außenraumproblemen die Abstrahlung in das Fernfeld abzubilden. Nach der Anwendung des entwickelten Programmcodes auf einfachere Modelle erfolgen Untersuchungen zur Intonation einer Blockfl{\"o}te. Hierzu wird das Fluid innerhalb und im Nahfeld des Instruments unter Ber{\"u}cksichtigung des turbulenten Str{\"o}mungsprofils, welches sich beim Spielen der Blockfl{\"o}te ausbildet, betrachtet. Im Ergebnis stehen die Eigenwerte des Instruments in Abh{\"a}ngigkeit von der gew{\"a}hlten Griffkombination. Zur Evaluierung der Ergebnisse und zur Untersuchung des Einflusses der Str{\"o}mung auf den Klang erfolgt der Vergleich mit den exakten Eigenfrequenzen. Die Galbrun-Gleichung wurde bereits von anderen Autoren untersucht und auf akustische Problemstellungen angewendet. Im Rahmen dieser Arbeit erfolgt jedoch erstmalig die Anwendung der Galbrun-Gleichung auf Eigenwertprobleme. Dar{\"u}ber hinaus sind der Autorin keine Arbeiten bekannt, die sich mit dreidimensionalen Modellen befassen. In der vorliegenden Arbeit werden somit erstmals komplexe dreidimensionale Modelle unter Anwendung der Galbrun-Gleichung untersucht.}, language = {de} } @inproceedings{RetkaMarburg, author = {Retka, Stefanie and Marburg, Steffen}, title = {Modal analysis of a fluid in an unbounded domain with finite and infinite elements}, series = {Proceedings of NOVEM 2012 - Noise and Vibration: Emerging Methods, Sorrento}, booktitle = {Proceedings of NOVEM 2012 - Noise and Vibration: Emerging Methods, Sorrento}, language = {en} } @inproceedings{RetkaMarburg, author = {Retka, Stefanie and Marburg, Steffen}, title = {Modalanalyse eines str{\"o}menden Fluids mit finiten und infiniten Elementen}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 38. Jahrestagung f{\"u}r Akustik, Darmstadt}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 38. Jahrestagung f{\"u}r Akustik, Darmstadt}, editor = {Hanselka, H.}, pages = {557 -- 558}, language = {de} } @inproceedings{RetkaMarburg, author = {Retka, Stefanie and Marburg, Steffen}, title = {Numerical computations of a fluid inside and around a recorder}, series = {Proceedings of Forum Acusticum 2011, Aalborg, D{\"a}nemark}, booktitle = {Proceedings of Forum Acusticum 2011, Aalborg, D{\"a}nemark}, pages = {145 -- 147}, abstract = {We present the sound propagation and sound radiation inside and around a three dimensional recorder model. The fluid inside and in the near field of the instrument is meshed by second order Lagrangian tetrahedra elements. To present the effects in the far field, infinite elements are added to the finite elements. As infinte elements we use complex conjugated Astley-Leis elements. The goal of our studies is the computation of the eigenmodes of all playable notes, as well as the determination of the radiation behaviour for different fingerings. In a first step, the results obtained by considering a static fluid are presented. When playing a recorder, the inserted air flow leads to an oscillation of the air column inside the instrument. The musician is able to influence the frequency of the note by varying the blowing pressure and therefore a fine-tuning of the sound can be achieved. In rotation afflicted flows, the sound propagation can be described by the Galbrun equation. In a first instance, we present the influence of the flow velocity on the eigenfrequencies for simple geometries. Those results are compared to the frequencies obtained with Helmholtz equation for static fluids.}, language = {en} } @inproceedings{MarburgRetkaMoebius, author = {Marburg, Steffen and Retka, Stefanie and M{\"o}bius, Franziska}, title = {Simulation and Experiment for Intonation of a Recorder}, series = {Analysis and description of music instruments using engineering methods, Halle}, booktitle = {Analysis and description of music instruments using engineering methods, Halle}, editor = {Birnbaum, C. and Ehricht, S. and Kaliske, M. and Saft, S.}, pages = {42 -- 49}, language = {en} } @article{RetkaHawkingsMarburg, author = {Retka, Stefanie and Hawkings, Stuart C. and Marburg, Steffen}, title = {An eigenvalue search algorithm for the modal analysis of a resonator in free space}, series = {Journal of Computational Acoustics}, volume = {19}, journal = {Journal of Computational Acoustics}, number = {1}, pages = {95 -- 109}, language = {en} } @inproceedings{RetkaMarburg, author = {Retka, Stefanie and Marburg, Steffen}, title = {Numerische Berechnung eines Fluids innerhalb und um einer Blockfl{\"o}te}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 37. Jahrestagung f{\"u}r Akustik, D{\"u}sseldorf}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 37. Jahrestagung f{\"u}r Akustik, D{\"u}sseldorf}, editor = {Becker-Schweitzer, J. and Notbohm, G.}, pages = {819 -- 820}, language = {de} } @inproceedings{RetkaMarburg, author = {Retka, Stefanie and Marburg, Steffen}, title = {Numerical Modal Analysis of a Recorder Fluid}, series = {Proceedings of 20th International Symposium on Music Acoustics (Associated Meeting of the International Congress on Acoustics), ISMA 2010, Sydney and Katoomba}, booktitle = {Proceedings of 20th International Symposium on Music Acoustics (Associated Meeting of the International Congress on Acoustics), ISMA 2010, Sydney and Katoomba}, editor = {Smith, J.}, pages = {3}, language = {en} } @inproceedings{RichterRetka, author = {Richter, Andreas and Retka, Stefanie}, title = {Sound production and radiation of resonator controlled edge tones}, series = {Proceedings of 20th International Congress on Acoustics, ICA 2010, Sydney}, booktitle = {Proceedings of 20th International Congress on Acoustics, ICA 2010, Sydney}, editor = {Burgess, M. and Davey, J. and Don, C. and McMinn, T.}, pages = {3}, language = {en} } @inproceedings{RetkaMarburg, author = {Retka, Stefanie and Marburg, Steffen}, title = {Numerical computations of a recorder fluid}, series = {Proceedings of 20th International Congress on Acoustics, ICA 2010}, booktitle = {Proceedings of 20th International Congress on Acoustics, ICA 2010}, editor = {Burgess, M. and Davey, J. and Don, C. and McMinn, T.}, pages = {3}, language = {en} } @inproceedings{RichterRetka, author = {Richter, Andreas and Retka, Stefanie}, title = {Schallproduktion und -abstrahlung resonatorgesteuerter Schneident{\"o}ne}, series = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 36. Jahrestagung f{\"u}r Akustik, Berlin}, booktitle = {Fortschritte in der Akustik - Plenarvortr{\"a}ge und Fachbeitr{\"a}ge der 36. Jahrestagung f{\"u}r Akustik, Berlin}, editor = {M{\"o}ser, M. and Schulte-Fortkamp, B. and Ochmann, M.}, pages = {587 -- 588}, language = {de} }