Near-wall turbulence alteration with the transpiration-resistance model

A set of boundary conditions called the Transpiration-Resistance Model (TRM) are investigated in altering near-wall turbulence. The TRM has been previously proposed by \citet{Lacis2020} as a means representing net effect surface micro-textures on their overlying bulk flows. It encompasses conventional Navier-slip relating streamwise and spanwise velocities to respective shears through slip lengths $\ell_x$ $\ell_z$. In addition, it features transpiration condition accounting for changes induced wall-normal velocity expressing terms variations wall-parallel $m_x$ $m_z$. Greater levels drag increase occur when more takes place at plane, with turbulent being predominately coupled shear component canonical can reproduce homogeneous structured roughness up ${k^+}\,{\approx18}$. this transitionally rough flow regime, must be empirically determined. \emph{transpiration factor} is defined product between lengths, i.e. $(m\ell)_{x,z}$. This factor contains compound occurring plane increased permeability, both which lead transport momentum direction. linear relation function observed regularly textured surfaces regime relations obtained show that such effective quantities suitable measures characterizing regime.