An earlier analysis based on second-order closure and the Bray-Moss-Libby model of premixed combustion is applied to infinite, planar turbulent flames which are oblique to the oncoming reactants and which have undeflected mean streamlines. In such flames all three mechanisms, dilatation, Reynolds shear stresses, and mean pressure gradient, contribute to the balance of turbulent kinetic energy. Examination of the appropriate conservation equations in primitive form indicates that the intensity of the fluctuations of the velocity component normal to the flame and the mean flux of product in that direction are independent of obliquity. Thus earlier findings regarding countergradient diffusion and production of turbulence due to the mean pressure gradient prevail in oblique flames. The mean flux of product in the tangential direction and the intensity of the fluctuations of the velocity component in that direction are calculated. It is found that the mean streamlines of parcels of reactants and products are significantly different from one another and from the mean streamline. The intensities downstream of highly oblique turbulent flames are predicted to lead to two-dimensional turbulence in the plane containing the normal and tangential coordinates.
ASJC Scopus subject areas
- Aerospace Engineering