TY - CHAP A1 - Retka, Stefanie A1 - Marburg, Steffen T1 - Numerical computations of a fluid inside and around a recorder T2 - Proceedings of Forum Acusticum 2011, Aalborg, Dänemark N2 - 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. Y1 - 2011 SP - 145 EP - 147 ER - TY - CHAP A1 - Marburg, Steffen A1 - Retka, Stefanie A1 - Möbius, Franziska ED - Birnbaum, C. ED - Ehricht, S. ED - Kaliske, M. ED - Saft, S. T1 - Simulation and Experiment for Intonation of a Recorder T2 - Analysis and description of music instruments using engineering methods, Halle Y1 - 2011 SP - 42 EP - 49 ER - TY - JOUR A1 - Retka, Stefanie A1 - Hawkings, Stuart C. A1 - Marburg, Steffen T1 - An eigenvalue search algorithm for the modal analysis of a resonator in free space JF - Journal of Computational Acoustics Y1 - 2011 VL - 19 IS - 1 SP - 95 EP - 109 ER - TY - CHAP A1 - Retka, Stefanie A1 - Marburg, Steffen ED - Becker-Schweitzer, J. ED - Notbohm, G. T1 - Numerische Berechnung eines Fluids innerhalb und um einer Blockflöte T2 - Fortschritte in der Akustik – Plenarvorträge und Fachbeiträge der 37. Jahrestagung für Akustik, Düsseldorf Y1 - 2011 SP - 819 EP - 820 ER -