JOINT SCALAR-VELOCITY PDF MODELING OF FINITE RATE CHEMISTRY IN A SCALAR MIXING LAYER

The joint scalar-velocity probability density function (pdf) modelling approach is here applied to the problem of mixing and chemical reacti on in a scalar mixing layer. The cases considered are of direct releva nce to the modelling of turbulent combustion applications and the main objectives of the work are: (i) To assess the applicability of joint scalar-velocity pdf solution methods in the context of realistic low D amkohler number turbulent reacting flows. (ii) To investigate a multi- scalar extension of a modified binomial Langevin scalar mixing model o f Valino and Dopazo. The latter is here used in conjunction with the g eneralised Langevin model for velocity statistics of Haworth and Pope. The experimental data sets by Bilger et al., obtained in chemically r eacting flows with Damkohler numbers of the order unity have been used to validate the approach. The excellent agreement obtained for both c onserved and reacting scalars indicates that the reaction-diffusion co upling is accurately represented by the binomial Langevin mixing model for this flow. Comparisons with linear-eddy model results of Kerstein are also presented.