A STOCHASTIC LAGRANGIAN MODEL FOR NEAR-WALL TURBULENT HEAT-TRANSFER

The modeling of near-wall turbulent heat transfer necessitates appropr iate description of near-wall effects, namely, molecular transport, pr oduction of turbulence by inhomogeneities, and dissipation of the temp erature fluctuations by viscosity. A stochastic Lagrangian model, base d on the velocity-composition joint probability density function (PDF) method, has been proposed. The proposed model, when compared with exp erimental and direct numerical simulation (DNS) data, overdamps the di ssipation of the temperature fluctuations in the inertial sublayer, bu t reaches the correct limit at the wall. The performance of the model has also been compared to the standard k-epsilon and the algebraic Rey nolds stress model (ARSM) for both constant heat flux and constant tem perature boundary conditions at large Reynolds numbers. The Lagrangian nature of the model helps eliminate numerical diffusion completely.