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On the alignment of strain, vorticity and scalar gradient in turbulent, buoyant, nonpremixed flames
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Elghobashi, S. E. Zhong, R. Boratav, O. N. |
| Copyright Year | 1999 |
| Description | 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 the 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 < F(sub st). The F approximately equals F(sub st) band shows strain-dominance resulting in vorticity/alpha alignment while F > F(sub st) (and F < F(sub st) for the vertical flame) band(s) show(s) vorticity/beta alignment. The implication of this result is that the scalar dissipation, epsilon(sub F), attains its maximum value always near F approximately equals F(sub st). These results are also discussed within the framework of recent dynamical results [Galanti et al., Nonlinearity 10, 1675 (1997)] suggesting that the Navier-Stokes equations evolved towards an attracting solution. It is shown that the properties of such an attracting solution are also consistent with our results of buoyant turbulent nonpremixed flames. |
| File Size | 3667762 |
| Page Count | 8 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20000030670 |
| Archival Resource Key | ark:/13960/t6k12179q |
| Language | English |
| Publisher Date | 1999-09-01 |
| Access Restriction | Open |
| Subject Keyword | Inorganic, Organic And Physical Chemistry Navier-stokes Equation Tensors Alignment Turbulent Flames Tensor Analysis Buoyancy Vorticity Scalars Gradients Flame Propagation Turbulent Diffusion Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
