DAGA 2010 - Deutsche Gesellschaft für Akustik eV
DAGA 2010 - Deutsche Gesellschaft für Akustik eV
DAGA 2010 - Deutsche Gesellschaft für Akustik eV
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Programm <strong>DAGA</strong> <strong>2010</strong> 179<br />
Schwingungen einer Struktur, das auch die Untersuchung des Körperschallflusses<br />
durch starre oder biegsame Strukturen ermöglicht. Somit<br />
ist der Sensor <strong>für</strong> die Maschinenakustik ein wertvolles Hilfsmittel zur Untersuchung<br />
der Strukturintensität. Ein weiterer Vorteil des Sensorarrays<br />
ist sein gegenüber einer Anzahl herkömmlicher Beschleunigungssensoren<br />
signifikant geringerer Preis sowie ein geringeres Gesamtgewicht,<br />
durch das die zu untersuchende Struktur nur minimal in ihren akustischen<br />
Eigenschaften verändert wird.<br />
Mi. 8:55 Grashof C 116 Modelle u. Methoden Aeroakustik II<br />
Computational Aeroacoustics of a Backward Facing Step<br />
M. Kaltenbacher a , J. Grabinger b , S. Becker c und F. Schäfer d<br />
a Alps-Adriatic University of Klagenfurt; b Univ. Erlangen-Nürnberg, Lehrstuhl<br />
<strong>für</strong> Sensorik; c Univ. Erlangen-Nürnberg, Prozessmaschinen und<br />
Anlagentechnik; d Universität Erlangen-Nürnberg<br />
Since the beginning of Computational Aeroacoustics (CAA), several numerical<br />
methodologies have been proposed, each trying to overcome<br />
the challenges that the specific problems under investigation pose for<br />
an effective and accurate computation of the radiated sound. The main<br />
difficulties that have to be considered for the simulation of flow noise<br />
problems include energy and length scale disparity, preservation of the<br />
multipole character of the acoustic sources and dispersion and dissipation<br />
occurring in numerical schemes. Due to the large disparities of<br />
length and energy scales between flow and acoustic quantities, the hybrid<br />
methodologies still remain the most commonly used approaches for<br />
aeroacoustic computations. In order to provide a basis for a real benchmark<br />
problem, we have performed highly resolved DNS (Direct Numerical<br />
Simulation) computations of a backward facing step with well defined<br />
boundary conditions for the flow. We will provide detailed analysis of the<br />
flow field as well as occurring acoustic field based on an enhanced Finite<br />
Element (FE) scheme solving Lighthill’s acoustic analogy, and will<br />
encourage other research groups to use our fluid flow data to test their<br />
computational aeroacoustic schemes.<br />
Mi. 9:20 Grashof C 116 Modelle u. Methoden Aeroakustik II<br />
Sound Source Terms of Coaxial Jets<br />
S.R. Koh, W. Schröder und M. Meinke<br />
Institute of Aerodynamics, RWTH Aachen<br />
Acoustic far-field is strongly influenced by multiple shear layers and density<br />
inhomogeneity. One of the fundamental changes is the local sound<br />
speed of the mixing layer since across the shear layer the acoustic waves<br />
undergo refraction. Moreover, the heat source is part of the sound<br />
source such that the pronounced temperature gradient causes louder<br />
acoustic fields. In the present study sound radiation in non-uniform density<br />
field is investigated by using coaxial jets. The coaxial jets are configured<br />
to have an unheated primary flow for one cold coaxial jet and
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