Turbulent nonpremixed scales

Turbulent nonpremixed flames contain a wide range of lengfh scales. For a given flame geomefry, fhe largest scales of furbulence are determined by the overall width of an unconfined jef flame or by fhe dimensions of the hardware that contain the flow. Therefore, the largest scales of turbulent motion are typically independent of Reynolds number. As the Re5molds number increases. 

DesJardin, P. E., and S. H. Frankel. 1998. Large-eddy simulation of a turbulent nonpremixed reacting jet Application and assessment of subgrid-scale combustion models. J. Physics Fluids 10(9) 2298-314. 

Wang, C.-H., Clemens, N. T., Varghese, R L., and Barlow, R. S. "Turbulent time Scales in a Nonpremixed Turbulent Jet Flame by Using High-Repetition Rate Thermometry." Combustion and Flame 152 (2008) 317-35. 

In the discussion above, we have considered only the velocity field in a turbulent flow. What about the length and time scales for turbulent mixing of a scalar field The general answer to this question is discussed in detail in Fox (2003). Here, we will only consider the simplest case where the scalar field 4> is inert and initially nonpremixed with a scalar integral length scale that is approximately equal to Lu. If we denote the molecular diffusivity of the scalar by T, we can use the kinematic viscosity to define a dimensionless number in the following way ... 

Wall, C., B. J. Boersma, and R Moin (2000). An evaluation of the assumed beta probability density function subgrid-scale model for large eddy simulation of nonpremixed, turbulent combustion with heat release. Physics of Fluids 12, 2522-2529. 

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