Alignment of Strain, Vorticity and Scalar and Gradient in Turbulent, Buoyant, Nonpremixed Flames

摘要

The alignment of vorticity and scalar gradient with the eigendirections of the rate of strain tensor is investigated in turbulent buoyant nonpremixed horizontal and vertical flames. The uniqueness of a buoyant nonpremixed flame is that it contains regions with distinct alignment characteristics. The strain-enstrophy angle Psi is used to identify these regions. Examination of vorticity field and the vorticity production in these different regions indicates that Psi and consequently the alignment properties near the flame surface identified by the mixture fraction band F approximately equals F (sub st) differ from those in the fuel region, F F (sub st) and the oxidizer region, F