Investigation of an assumed PDF approach for finite-rate chemistry

This article deals with high-speed turbulent combustion based on finite-rate chemistry. An assumed probability density function (PDF) approach is used to account for turbulence chemistry interaction. The PDFs employed are a clipped Gaussian distribution for temperature and a joint multivariate g -PDF for species mass fractions. The definition of both PDFs is based on higher order moments obtained from additional transport equations. The objective of this work is to compare different variance transport equations (energy, sensible energy, and temperature) from which the required temperaturevariance is recovered. Moreover, the influence of closed and unclosed correlations of these variance transport equations is investigated. It is shown that some higher order correlations as well as commonly used approximations for the temperature variance recovery may result in significant errors. This is the reason for modifications and for the use of a temperature variance transport equation. Numerical results are compar...