Abstract
A premixed turbulent flame stabilized behind a bluff body and oscillating due to oncoming flow pertur- bations is studied. A simple kinematic model of such a flame was developed by Bowling (J. Fluid Mech. 394:51, 1999) who reduced the combustion process to the propagation of an infinitely thin flame at a constant speed. The goal of this work is to extend the model by taking into account the real structure of premixed turbulent flames and the development of turbulent flame speed and thickness. For these purposes, the so-called Flame Speed Closure model for multi-dimensional simulations of premixed turbulent combustion is adapted and combined with the aforementioned Bowling model. Simulations of the heat release rate dynamics have been performed. Typical results show that the oscillations in the integrated heat release rate follow the velocity oscillations with certain time delay. The delays computed using the Bowling and the above approaches are different, thus indicating the importance of resolving flame structure when modeling ducted flame oscillations.
