Citation
Lasheras, Juan C. and Liñán Martínez, Amable and Lecuona Newman, Antonio and Rodríguez Aumente, Pedro A.
(1992).
Vorticity dynamics in three-dimensional pulsating co-flowing jet diffusion flames.
In: "Symposium (International) on Combustion (24. 1992. Sydney)", 5-10 Jul 1992, Sydney. ISBN 0082-0784.
Abstract
The vorticity dynamics in the near field of laminar (Re = 103) co-flowing jets subjected to the single or combined effeets of axial and azimuthal forcing is analyzed. It is shown that the interaction of the three-dimensional vortex structure resulting from the growth of the two and three-dimensional instabilities may result in large changes in the entrainment and mixing characteristics of the jet. For each azimuthal forcing, and for a fixed velocity ratio between the inner and outer jet, we show the existence of several instability modes leading to a pattern of lateral ejections of closed vortex loops. These modes and their topological changes are analyzed in view of the three-dimensional inviscid induction of the two concentric array of vortex rings emanating from the j e t s exit nozzle. For the case of methane-air diffusion flames, fiow visualizations revealed the existence of qualitatively similar patterns of closed fíame cells and fingers.