A series of prototype-scale laboratory experiments was performed in the Aberdeen Oscillatory Flow Tunnel to investigate the intra-wave sediment transport processes in the ripple regime. Detailed measurements of velocities and concentrations were carried out for three different regular oscillatory flow conditions. It is found that the time- and bed-averaged concentrations fit an exponential profile reasonably well, and that the concentration decay length is strongly related to the ripple height. The intrawave concentration field is dominated by the formation and ejection of vortices on the onshore (in the direction of flow asymmetry) ripple flank. In a lower layer of about two ripple heights, the net current-related flux and net wave-related flux are in the offshore direction and the wave-related flux dominates. Higher up in the flow the net wave-related flux is still offshoredirected, but the net current-related flux is onshore-directed and is dominant, resulting in an onshore total net flux.
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