caa a22 4500 477093213 CHVBK 20180405111520.0 cr unu---uuuuu 170330e19960201xx s 000 0 eng 10.1007/BF00192668 doi (NATIONALLICENCE)springer-10.1007/BF00192668 Instability of buoyant diffusion flames [Elektronische Daten] [A. Lingens, M. Reeker, M. Schreiber] Buoyant jet diffusion flames are known to exhibit large scale vortical flow structures strongly interacting with flame structures. In the present work, the formation and evolution of coherent flow structures is studied in a methane/ air coflow arrangement. This is accomplished by utilizing visualization techniques (planar laser induced hydroxyl fluorescence and Mie-scattering) and Laser Doppler Velocimetry. A striking repeatability and correlation of evolving coherent structures of the air co-flow and the reaction zone is observed. In the transitional region, flow and flame structures oscillate at very pure frequencies ranging from 10-15 Hz. A local absolutely unstable velocity profile close to the burner rim seems to be responsible. Self-excited axisymmetric wavelike structures propagate up- and downstream of this location. We study the influence of the exit velocities and the type of coflowing oxidizer (air or oxygen) on the location of transition to periodic flow structures and related frequencies. Conditional averages of image and velocity data are employed to describe the evolution of coherent flow structures and their interaction with flame structures. Springer-Verlag, 1996 Lingens A. Lehrstuhl für Technische Thermodynamik, RWTH Aachen, D-52056, Aachen, Germany aut Reeker M. Lehrstuhl für Technische Thermodynamik, RWTH Aachen, D-52056, Aachen, Germany aut Schreiber M. Lehrstuhl für Technische Thermodynamik, RWTH Aachen, D-52056, Aachen, Germany aut Experiments in Fluids Springer-Verlag 20/4(1996-02-01), 241-248 0723-4864 20:4<241 1996 20 348 https://doi.org/10.1007/BF00192668 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00192668 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lingens A. Lehrstuhl für Technische Thermodynamik, RWTH Aachen, D-52056, Aachen, Germany aut NATIONALLICENCE 700 1- Reeker M. Lehrstuhl für Technische Thermodynamik, RWTH Aachen, D-52056, Aachen, Germany aut NATIONALLICENCE 700 1- Schreiber M. Lehrstuhl für Technische Thermodynamik, RWTH Aachen, D-52056, Aachen, Germany aut NATIONALLICENCE 773 0- Experiments in Fluids Springer-Verlag 20/4(1996-02-01), 241-248 0723-4864 20:4<241 1996 20 348 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer