Sand Ripples and Bedforms
A full-scale experimental study is carried out to study the geometric characteristic of wave-generated sand ripples using a large-scale oscillatory water tunnel. The tests cover a variety of sinusoidal flows, under which uniform 2-dimensional ripples are generated after O(1000) periods for well-sorted coarse sand (d50=0.51mm). Results show that the generic ripple shape changes from more parabolic-alike to sinusoidal-alike as Shields parameter increases. Due to this reason, the ripple crests are more rounded for large Shields parameter cases. Meanwhile, more energetic flows can flatten the ripples (steepness decreases), resulting in a clear decreasing trend of maximum slope on ripple flanks.