Effect of spatially distributed wall concentration on the wall-flux of a passive scalar field in a laminar to turbulent transition boundary layer

摘要

We analyze the effect of spatially distributed wall concentration on the wall-flux of a passive scalar field in a laminar to turbulent transition boundary layer formed around a flat plate. Numerical simulations of the Reynolds averaged transport models are considered for obtaining the distribution of the velocity, turbulence and the scalar concentration field. The shear stress transport (SST) model for turbulence kinetic energy and specific rate of dissipation, tailored for transition boundary layer, is considered for closing the momentum equations. The scalar transport equation is closed by the gradient diffusion hypothesis. The transition boundary layer and the spatially non-homogeneous wall concentration result in a complex spatial variations in the wall-flux of the passive scalar. We show that the apparent complexity can be addressed with the help of Reynolds analogy. Subsequently, we develop a correlation for the scalar flux as a perturbed version of the Reynolds analogy. (C) 2020 Elsevier B.V. All rights reserved.