Modeling the Response of Turbulent Flames to Harmonic Forcing

Abstract

ABSTRACTThis article analyzes the response of a turbulent, premixed flame to harmonic forcing. This problem has been worked extensively for laminar flames, and the key parameters influencing the flame transfer function are well understood. For turbulent flames, several prior studies have utilized a “quasi-laminar” approach, by utilizing the time-averaged flame position and ensemble-averaged disturbance field, as inputs to what is otherwise identical to the laminar problem. More generally, the manner in which turbulent flames respond to harmonic disturbances is not amenable to analytical solutions because of the nonlinear interactions between stochastic flow disturbances and harmonic flame wrinkling. We utilize a turbulent burning velocity closure proposed by Shin and Lieuwen (2013), who showed that the ensemble-averaged turbulent burning rate for a harmonically forced flame is proportional to the ensemble-averaged flame curvature. Shin and Lieuwen (2013) previously used it to analyze the ensemble-averaged...