Title: Visualisation of statistically periodic coherent structures in turbulent flows using a phase-locked averaging method

Authors: Peter Habisreuther, Thomas Lischer, Weidong Cai, Werner Krebs, Nikolaos Zarzalis, Henning Bockhorn

Addresses: Engler-Bunte-Institute, Division for Combustion Technology, University of Karlsruhe (TH), Engler-Bunte-Ring 1, 76131 Karlsruhe, Germany. ' Engler-Bunte-Institute, Division for Combustion Technology, University of Karlsruhe (TH), Engler-Bunte-Ring 1, 76131 Karlsruhe, Germany. ' Siemens Power Generation, 4400 Alafaya Trail, MC: Q3042, Orlando, FL 32826, USA. ' Siemens Power Generation, Energy Sector/PG PE413, Mellinghoferstrasse 55, 45466 Mulheim, Germany. ' Engler-Bunte-Institute, Division for Combustion Technology, University of Karlsruhe (TH), Engler-Bunte-Ring 1, 76131 Karlsruhe, Germany. ' Engler-Bunte-Institute, Division for Combustion Technology, University of Karlsruhe (TH), Engler-Bunte-Ring 1, 76131 Karlsruhe, Germany

Abstract: Coherent structures are the focus of many flow investigations, although their contribution to turbulent mixing is not well understood. When occurring together with high intense turbulent mixing, these structures require statistical methods for visualisation and analysis of simulation results obtained using high-resolution numerical schemes, such as LES or DES. The method of |phase-locked| averaging separates transient processes with a given frequency. This paper reveals an online formulation for the phase-locked averaging technique at a certain frequency to be set by the user. The method is demonstrated for two realistic flow configurations, an isothermal double-concentric combustor flow and a jet-in-crossflow situation.

Keywords: phase-locked averaging; LES; DES; swirl; jet-in-crossflow; visualisation; coherent structures; turbulent flows; turbulent mixing; combustor flow; computational fluid dynamics; CFD.

DOI: 10.1504/PCFD.2008.019481

Progress in Computational Fluid Dynamics, An International Journal, 2008 Vol.8 No.5, pp.276 - 287

Published online: 14 Jul 2008 *

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