On the solidity parameter in canopy flows

We have performed high-fidelity simulations of turbulent open-channel flows over submerged rigid canopies made cylindrical filaments fixed length $l=0.25H$ ($H$ being the domain depth) mounted on wall with an angle inclination $\theta$. The is free parameter that sets density canopy by varying its frontal area. canopy, based solidity $\lambda$, a widely accepted criterion defining ongoing flow regime, low values ($\lambda \ll 0.1$) indicating sparse and higher > dense regime. All numerical predictions been obtained considering same nominal bulk Reynolds number (i.e. $Re_b=U_b H/\nu = 6000$). consider nine configurations canopies, $\theta$ symmetrically around $0{\deg}$ in range $\theta\in [\pm 78.5{\deg}]$, where positive angles define inclined direction (with grain) $\theta=0{\deg}$ corresponds to wall-normally canopy. study compares identical inclining opposite assesses efficacy as representative parameter. It found when inclined, actual regime differs substantially from one straight shares criteria solely this are not robust. Finally, new phenomenological model describing interaction between coherent structures populating region outer given.