Berlin 2012 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 16: Fluid dynamics and turbulence II

DY 16.7: Vortrag

Mittwoch, 28. März 2012, 11:45–12:00, MA 144

Investigations of cavity noise generation on a cylinder — •Tim Homeyer1, Nils Kirrkamm1, Christopher Haut3, Manfred Schultz-von Glahn2, Gerrit Kampers1, Joachim Peinke1, Volker Mellert3, and Gerd Gülker11ForWind - Center for Wind Energy Research, Institute of Physics, University of Oldenburg — 2ITAP - Institut für Technische und Angewandte Physik GmbH, Oldenburg — 3Acoustics, Institute of Physics, University of Oldenburg

Cavity noise generation was under investigation in various studies and is today of particular interest for e.g. the aeronautical and automotive industry. The boundary layer plays a major role in the characterization of the flow in and around the cavity. In this work a small overflowed cavity on a cylinder at flow velocity ramps up to 45 m/s is under investigation. It turns out, that the standard cavity noise theory is not applicable for this particular setup.
Acoustical, PIV, smoke and Hot-Wire measurements were performed. A sudden transition of the circulating flow (drag crisis) at the expected Reynolds number lead to vorticies flow over the cavity. The onset of the acoustic radiation of the cavity is simultaneous with this transition and shows a strong hysteresis. CFD simulations with OpenFoam are performed to investigate the three-dimensional flow instabilities. All results indicate that the Kelvin-Helmholtz instabilities are the reason for the acoustic noise generated by the cavity.
In this presentation measurements and simulations will be presented and discussed.

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