ASSUMED AND EVOLUTION PROBABILITY DENSITY-FUNCTIONS IN SUPERSONIC TURBULENT COMBUSTION CALCULATIONS

The objective of this investigation is to compare the use of assumed p robability density function (PDF) approaches for modeling supersonic t urbulent reacting flowfields with the more elaborate approach where th e PDF evolution equation is solved, previous calculations using assume d PDFs have shown modest improvements in the prediction of mean flow v ariables when compared with experimental data, However, these PDFs wer e unable to predict the higher order correlations with any reasonable degree of accuracy. Solving the evolution equation for the PDF did sho w slight improvements in these correlations when compared with experim ent, but at a substantial cost in computer storage and time, Both appr oaches yielded comparable mean now quantities.