Secondary currents and very-large-scale motions in open-channel flow over streamwise ridges

Financial support was provided by the EPSRC/UK grant ‘Bed friction in roughbed free-surface flows: a theoretical framework, roughness regimes, and quantification’ (grant EP/K041088/1). Discussions with I. Marusic (University of Melbourne) and B. Ganapathisubramani (University of Southampton) are greatly appreciated.Peer reviewedPublisher PD