Direct Simulation of a Passive Diffusion Flame in Sheared and Unsheared Homogeneous Turbulence
The paper presents the results of direct numerical simulation of two homogeneous shear flows of different initial strain number (St) and a decaying isotropic turbulence with an infinite-rate chemical reaction between two species but without heat release. The simulations were performed using a (96)3 computational grid and an initial Taylor’s Reynolds number, Re λ, of 25. The results show that shear flattens the reaction surface due to the augmented strain rates resulting from vortex stretching. The time evolution of the scalar pdf shows that the higher the strain number is the higher the scalar mixing rate. The directions of the instantaneous scalar flux and the instantaneous scalar gradient are uncorrelated, thus indicating that turbulent scalar transport is a nongradient mechanism.
KeywordsDirect Numerical Simulation Mixture Fraction Direct Simulation Flame Surface Scalar Dissipation Rate
Unable to display preview. Download preview PDF.
- Elghobashi, S. E. (1977): Studies in the prediction of turbulent diffusion flames. Studies in Convection, (B. E. Launder ed.), 2, 141–187Google Scholar
- Elghobashi, S. E., Gerz, T., Schumann, U. (1987): Direct simulation of the initial development and the homogeneous limit of the thermal mixing layer. Sixth Symposium on Turbulent Shear Flows 511–516, Toulouse, FranceGoogle Scholar
- Nomura, K. K., Elghobashi, S. E. (1990): Direct simulation of an isothermal non-premixed flame in homogeneous turbulent shear flow. Paper AIAA 90–148, 28th Aerospace Sciences MeetingGoogle Scholar
- Zeldovich, Y. B. (1949): On the theory of combustion in initially unmixed gases. Zhur. Tekhn. Fiz. 19, 1950. English Translation, N.A.C.A. Tech. Mem. No. 1296Google Scholar