Binary Scalar Mixing and Reaction in Homogeneous Turbulence: Some Linear Eddy Model Results

The linear eddy model (LEM) of Kerstein (Kerstein, A. R. Combust. Sci. Technol. 1988, 60, 391–421; J. Fluid Mech. 1991, 231, 361–394; Phys. Fluids A 1991, 3 (5), 1110–1114; J. Fluid Mech. 1992, 240, 289–313) is used to simulate the mechanism of scalar mixing from an initial binary state in incompressible, homogeneous turbulence. The simulated results are used to measure the limiting rate of mean reactant conversion in a chemical reaction of the type F + rO → (1 + r)products under isothermal and nonpremixed conditions. The objective of the simulations is to assess the performance of the closed-form analytical expressions obtained by Madnia et al. (Madnia, C. K.; Frankel, S. H.; Givi, P. Theor. Comput. Fluid Dyn. 1992, 4, 79–93) based on the amplitude mapping closure (Kraichnan, R. H. Bull. Am. Phys. Soc. 1989, 34, 2298; Chen, H.; Chen, S.; Kraichnan, R. H. Phys. Rev. Lett. 1989, 63 (24), 2657-2660; Pope, S. B. Theor. Comput. Fluid Dyn. 1991, 2, 255-270) for the evaluation of the mean reactant conversion rate. This assessment is made for various flow conditions with different asymptotic statistical behavior.