An investigation of the Prandtl number effect on turbulent heat transfer in channel flows by large eddy simulation

An investigation of turbulent open channel flow with heat transfer by large eddy simulation

“…The LES approach, coupled with dynamic SGS turbulent stress and heat flux models, has been already employed to study fully developed turbulent two-walled channel flow with scalar transfer at high Prandtl and Schmidt number [22,25]. Comparison of the LES results with known turbulent statistics and well-established correlations for the scalar transfer rate have revealed a very good quantitative agreement at high Prandtl and Schmidt numbers.…”

“…In the vertical direction, to increase the grid resolution near the top free surface and bottom wall, respectively, the grid distribution is stretched so that it is sufficient to resolve the viscous sublayer and diffusive sublayer near the boundary [32,33]. The grid spacing is determined by the requirement that at least three points are within the diffusive sublayer near each boundary [25,26].…”

“…In the present calculation, the average is taken in the plane parallel to the wall plate [25][26][27][28].…”

“…Recently, an improved dynamic SGS model, including subgrid turbulent stress and heat flux models, for thermally stratified flow was proposed and applied to the thermally stratified turbulent channel flows for investigating the coupled shear and buoyancy effects on turbulent heat transfer [23,24]. On account of the improvements made by the SGS models, it becomes highly tempting to use the dynamic SGS model for studying turbulent flow with scalar transfer at high Prandtl or Schmidt numbers [22,25,26].…”

Characteristics of turbulence transport for momentum and heat in particle-laden turbulent vertical channel flows

“…The numerical algorithm used to solve Eqs. (1)-(3) was based on a semi-implicit, fractional step method [38]. The time integration incorporates an implicit second-order Crank-Nicolson method for the viscous terms and an explicit third-order Runge-Kutta scheme for the non-linear terms and the feedback terms.…”