Properties of the scalar variance transport equation in turbulent channel flow

Abstract

The asymptotic scaling structure of the total scalar variance equation is investigated for fully developed turbulent channel flow subjected to uniform scalar generation. The total scalar variance balance has a four-layer structure similar to that of the total kinetic energy balance, as previously investigated by Zhou and Klewicki [Phys. Rev. Fluids 1, 044408 (2016)]. Direct numerical simulation data are used to quantify the leading balance structure. These data cover the friction Reynolds number up to δ + = 4088 and Prandtl number ranging between Pr = 0.2 and 1.0. Of the layers empirically characterized, the inner-normalized width of the third layer is analytically verified to be δ + − √ δ +..