Large Eddy Simulation of Entropy Generation in a Turbulent Mixing Layer
Entropy transport equation is considered in large eddy simulation (LES) of turbulent flows. The irreversible entropy generation in this equation provides a more general description of subgrid scale (SGS) dissipation due to heat conduction, mass diffusion and viscosity effects. A new methodology is developed, termed the entropy filtered density function (En-FDF), to account for all individual entropy generation effects in turbulent flows. The En-FDF represents the joint probability density function of entropy, frequency, velocity and scalar fields within the SGS. An exact transport equation is developed for the En-FDF, which is modeled by a system of stochastic differential equations, incorporating the second law of thermodynamics. The modeled En-FDF transport equation is solved by a Lagrangian Monte Carlo method. The methodology is employed to simulate a turbulent mixing layer involving transport of passive scalars and entropy. Various modes of entropy generation are obtained from the En-FDF and analyzed. Predictions are assessed against data generated by direct numerical simulation (DNS). The En-FDF predictions are in good agreements with the DNS data.
Bulletin of the American Physical Society, 66th Annual Meeting of the APS Division of Fluid Dynamics
Safari Qariq, Mehdi; Sheikhi, M. Reza H.; and Hadi, Fatemeh, "Large Eddy Simulation of Entropy Generation in a Turbulent Mixing Layer" (2013). Engineering Faculty Publications. 128.
Sheikhi, M.R.H., Safari, M. and Hadi, F. "Large Eddy Simulation of Entropy Generation in a Turbulent Mixing Layer," Bulletin of the American Physical Society, 66th Annual Meeting of the APS Division of Fluid Dynamics, Vol. 58, No. 18, Pittsburgh, PA, November 24-26, 2013.