Author(s): Pradeep C. Fernando; Junke Guo; Pengzhi Lin
Keywords: Bed roughness; bed shear stress; theoretical model; velocity distribution; wave–current interaction
Abstract: This research presents an experimental study in a spatial wave basin for nonlinear interaction of regular waves with a perpendicular shear current over a movable bed. Detailed measurements were collected for current velocity profiles under different conditions, from which the bed shear stress and apparent roughness heights were determined. These combined with the measured velocities were used to validate theoretical models for wave–current interaction at an angle. It is found that for small wave heights all models agree well with the measured mean current velocities in the combined flow, while for larger wave heights only two models are reasonably close to the measurements for current velocities. For very large waves none of the models adequately describes the near-surface current velocities, which deviate significantly from the log-law. For the bed shear stress and the apparent roughness, only one model describes the measured data well.