Near bed flow characteristics over the patch and non-patch zone due to pure wave

An experimental study was conducted in a laboratory flume to investigate various velocities and turbulent characteristics over the patch and the non-patch zones for a sand bed under the influence of wave only. The difference in the near-bed flow characteristics over the patch and non-patch zones under a wavey environment is investigated and discussed. Results revealed that the vertical and longitudinal velocities were generally more significant in the patch zone than in the non-patch zone. Further, the quadrant analysis technique is applied to the recorded velocity fluctuations; the obtained result shows that ejection, sweep, outward, and inward interactions in the patch zone were more substantial than in the non-patch zone. This resulted in more active sediment dynamics in the patch zone compared to the non-patch zone leading to the faster formation of ripples in the patch zone.