TY - JOUR A1 - Oberleithner, Kilian A1 - Sieber, Moritz A1 - Nayeri, Christian A1 - Paschereit, Christian A1 - Petz, Christoph A1 - Hege, Hans-Christian A1 - Noack, Bernd A1 - J. Wygnanski, Israel T1 - Three-dimensional Coherent Structures of the Swirling Jet Undergoing Vortex breakdown: Stability Analysis and Empirical Mode Construction JF - J. Fluid Mech. Y1 - 2011 U6 - https://doi.org/10.1017/jfm.2011.141 VL - 679 SP - 383 EP - 414 ER - TY - JOUR A1 - Oberleithner, Kilian A1 - Sieber, Moritz A1 - Nayeri, Christian A1 - Paschereit, Christian A1 - Petz, Christoph A1 - Hege, Hans-Christian A1 - Noack, Bernd A1 - Wygnanski, Israel T1 - Self Excited Oscillations in Swirling Jets: Stability Analysis and Empirical Mode Construction JF - Bulletin of the American Physical Society Y1 - 2010 UR - http://meetings.aps.org/link/BAPS.2010.DFD.GE.8 N1 - 63rd Annual Meeting of the APS Division of Fluid Dynamics, November 21-23, 2010, Long Beach, CA VL - 55 IS - 16 SP - GE.00008 ER - TY - JOUR A1 - Petz, Christoph A1 - Oberleithner, Kilian A1 - Sieber, Moritz A1 - Nayeri, Christian A1 - Paschereit, Oliver A1 - Wygnanski, Israel A1 - Noack, Bernd A1 - Hege, Hans-Christian T1 - Global Modes in a Swirling Jet Undergoing Vortex Breakdown JF - Physics of Fluids Y1 - 2011 U6 - https://doi.org/10.1063/1.3640007 VL - 23 SP - 091102 PB - Awarded Visualization; First Prize at 28th Annual Gallery of Fluid Motion exhibit, held at the 63th Annual Meeting of the American Physical Society, Division of Fluid Dynamics (Long Beach, CA, USA, November 21-23, 2010). ER - TY - JOUR A1 - Lacarelle, Arnaud A1 - P. Moeck, Jonas A1 - Paschereit, Christian A1 - Gelbert, Gregor A1 - King, Rudibert A1 - M. Luchtenburg, Dirk A1 - Noack, Bernd R. A1 - Kasten, Jens A1 - Hege, Hans-Christian T1 - Modeling a Fuel/Air Mixing to Control the Pressure Pulsations and NOx Emissions in a Lean Premixed Combustor JF - Active Flow Control II Y1 - 2010 U6 - https://doi.org/10.1007/978-3-642-11735-0_20 VL - 108 SP - 307 EP - 321 PB - Springer, Berlin ER - TY - GEN A1 - Sieber, Moritz A1 - Kuhn, Alexander A1 - Hege, Hans-Christian A1 - Paschereit, C. Oliver A1 - Oberleithner, Kilian T1 - A Graphical Representation of the Spectral Proper Orthogonal Decomposition T2 - 68th Annual Meeting of the APS Division of Fluid Dynamics, Gallery of Fluid Motion, Nov 22-24, 2015, Boston, MA, USA. N2 - We consider the spectral proper orthogonal decomposition (SPOD) for experimental data of a turbulent swirling jet. This newly introduced method combines the advantages of spectral methods, such as Fourier decomposition or dynamic mode decomposition, with the energy-ranked proper orthogonal decomposition (POD). This poster visualizes how the modal energy spectrum transitions from the spectral purity of Fourier space to the sparsity of POD space. The transition is achieved by changing a single parameter – the width of the SPOD filter. Each dot in the 3D space corresponds to an SPOD mode pair, where the size and color indicates its spectral coherence. What we notice is that neither the Fourier nor the POD spectrum achieves a clear separation of the dynamic phenomena. Scanning through the graph from the front plane (Fourier) to the back plane (POD), we observe how three highly coherent SPOD modes emerge from the dispersed Fourier spectrum and later branch out into numerous POD modes. The spatial properties of these three individual SPOD modes are displayed in the back of the graph using line integral convolution colored by vorticity. The first two modes correspond to single-helical global instabilities that are well known for these flows. Their coexistence, however, has not been observed until now. The third mode is of double- helical shape and has not been observed so far. For this considered data set and many others, the SPOD is superior in identification of coherent structures in turbulent flows. Hopefully, it gives access to new fluid dynamic phenomena and enriches the available methods. Y1 - 2015 ER -