The occurrence of secondary flows is investigated for three-dimensional sinusoidal
roughness where the wavelength and height of the roughness elements are systematically …

Secondary flows can develop in turbulent boundary layers that grow over surfaces with
spanwise inhomogeneities. In this article, we demonstrate the formation of secondary flows …

Small drag-reducing riblets and larger drag-increasing ridges are longitudinally invariant
and laterally periodic surface structures that differ only in the details of their lateral periodicity …

Turbulent flow over a surface with streamwise-elongated rough and smooth stripes is
studied by means of direct numerical simulation (DNS) in a periodic plane open channel …

Aiming to study the rough-wall turbulent boundary layer structure over differently arranged
roughness elements, an experimental study was conducted on flows with regular and …

Lattice Boltzmann direct numerical simulation of turbulent open-channel flows over
randomly distributed hemispheres at is carried out to reveal the influence of roughness …

Direct numerical simulations (DNS) are used to systematically investigate the applicability of
the minimal-channel approach (Chung et al., J. Fluid Mech., vol. 773, 2015, pp. 418–431) for …

Recent developments in neural networks have shown the potential of estimating drag on
irregular rough surfaces. Nevertheless, the difficulty of obtaining a large high-fidelity dataset …

Scaling of rough-wall turbulence by the roughness height and steepness Page 1 J. Fluid Mech.
(2020), vol. 900, R7, doi:10.1017/jfm.2020.542 Scaling of rough-wall turbulence by the …

Despite decades of research, a universal method for prediction of roughness-induced skin
friction in a turbulent flow over an arbitrary rough surface is still elusive. The purpose of the …