Velocity measurements close to rippled beds in oscillatory flow

Abstract

The results are reported of velocity measurements in oscillatory flow over rippled beds. Velocities were measured with a laser-doppler anemometer in both an oscillating tray rig and an oscillatory flow water channel. Both self-formed and artificial ripples were examined. In addition, some measurements were made with an apparently plane bed with intense sediment motion. The experimental results were compared with the predictions of Kalkanis (1964), Kajiura (1968), Bakker (1973, 1974) and Sleath (1974). The closest agreement between theory and experiment was obtained with the method of Sleath. Measurements of the Eulerian drift velocities showed drift towards the adjacent ripple crest in the immediate vicinity of the bed and away from the crest further out.