Some Specific Characteristics of Turbulence in the Reactive Wakes of Bluff Bodies
The results of a detailed experimental analysis of the flows associated with bluff-body stabilized premixed combustion are presented. The experimental setup has been designed to facilitate as much as possible the test of numerical predictions of such a flow geometry. The boundary conditions are well defined and easy to reproduce from a numerical point of view. The results reported here are based principally on velocity measurements using a four-beam two-color laser Doppler velocimeter. A complete restructuring of the instantaneous flow structure induced by dramatic changes of the large-scale motion properties is observed when combustion is developing in the wake. The reacting wakes are characterized by the absence of the vortex shedding observed in inert wakes, but depending on the equivalence ratio of the incoming mixture, a longitudinal pulsation associated with the symmetric flapping of the flame fronts anchored at the flame holder edges can be observed