Hybrid multiple mapping conditioning modeling of local extinction

Hybrid multiple mapping conditioning modeling of local extinction

Multiple mapping conditioning (MMC) explicitly includes a link between the physical velocity and the conditioning variable. The usual method of obtaining values for the conditional physical velocity is to define the value of the conditioning variable and use a model for the velocity. In contrast to the conditional moment closure (CMC) approach, the conditioning variable is not a real quantity and hence provides greater flexibility in its definition. The hybrid binomial Langevin–MMC model has the advantage of naturally incorporating velocity–scalar interactions through the binomial Langevin model and the joint probability density function (PDF) is here used to define a reference variable for the MMC part of the model. The current approach has the advantage that difficulties encountered with the binomial Langevin model in modeling scalars with non-elementary bounds are removed. The formulation of the closure leads to locality in scalar space and permits the use of simple approaches for transport in the reference space. The evaluation of the technique is here extended to a jet flame with moderately-high levels of extinction (Sandia Flame E). A direct comparison with experimental data and the EMST (Euclidean minimum spanning tree) model for temperature, species concentrations and burning indexes suggests that the approach performs well.

© 2012 The Combustion Institute. Published version deposited in accordance with the copyright policy of the publisher.