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AK: Akustik

AK 5: Thermo- und Strömungsakustik (Sitzungsorganisation: Martin Ochmann und Rafael Piscoya, Berlin)

AK 5.6: Hauptvortrag

Dienstag, 8. März 2005, 14:30–15:00, TU EB222

Acoustic perturbation equations for reacting flows — •Thanh Phong Bui, Matthias Meinke, and Wolfgang Schröder — Aerodynamisches Institut, RWTH Aachen,Wüllnerstr. zw. 5 u. 7, 52062 Aachen

In the present work, acoustic perturbation equations (APE) for the omputational aeroacoustics (CAA) simulation are proposed to investigate noise generated by a turbulent non-premixed jet flame in unbounded space using a hybrid LES/CAA approach. The homogeneous APE system describes the wave propagation in a non-uniform mean flow and is hydrodynamically stable for arbitrary mean flows in contrast to the linearized Euler equations (LEE). To derive the extended APE system, which is also valid for reacting flows, the governing equations for reacting flows are rearranged such that the left-hand side describes the original homogeneous APE system, whereas the right-hand side (RHS) consists of all non-linear flow effects including the sources related to chemical reactions. The numerical approach is a two-step method, the first of which is based on a large eddy simulation (LES), followed by the CAA simulation to compute the acoustical field. In general, an acoustic monopole behavior with a small directivity can be observed, i.e., the main combustion noise characteristic, the monopole nature, caused by unsteady heat release could be verified.