ABSTRACT
When heat flow transitions into turbulence, both shear stress and heat transfer from the surface increase due to turbulent mixing. However, in a fully turbulent region, both shear stress and heat transfer slightly decrease again due to turbulent boundary-layer thickness growing along the surface. This chapter discusses external and internal flow and heat transfer problem in a fully turbulence region. A laminar sublayer is developed at a very-near-wall region where turbulent mixing is damped due to viscous effect. In intermediate-level heat transfer, the chapter focuses on how to derive Reynolds-Averaged Navier-Stokes equation and introduces the concept of turbulent viscosity and turbulent Prandtl number; Reynolds analogy; Prandtl mixing length theory; and law of wall for velocity and temperature profiles. It also introduces turbulent flow heat transfer coefficients derived from law of wall velocity and temperature profiles and their comparisons with the heat transfer correlations from experiments.
