Premixed flames in stagnating turbulence part IV: A new theory for the Reynolds stresses and Reynolds fluxes applied to impinging flows

We extend an earlier asymptotic analysis to calculate the Reynolds stresses and fluxes in a turbulent premixed reactant stream impinging on a wall. A critical examination of the models far pressure fluctuations is an essential element of the analysis; involved is an extension of the Bray-Moss-Libby (BML) decomposition to pressure gradients and the modeling of the contributions from reactants, products, and flamelets. A new set of second moment equations results. Comparison is made with two sets of experimental results involving premixed turbulent reactants impinging on a wall. The theory is then exploited to demonstrate differences between flames adjacent to the wall and those which are free-standing. The implications of our findings with respect to other turbulent reacting flows are discussed. (C) 1999 by The Combustion Institute.