Evolution of bed-forms due to associated wave turbulence over a sloping sand bed similar to shoaling zone of sea coast – An experimental approach

This paper presents the impact of near-bed turbulence due to only waves on a sediment bed to analyze the bedform evolutions and formation of ripples over a sloping bed of fine sediments in a laboratory flume. Measurements were made on the development of bedforms and the specific properties related to ripple formations. The geometric characteristics of ripples were recorded at multiple locations along the sloping bed in equilibrium condition. The results offered a significant understanding of the correlation between wave characteristics on a sloping bed and the shape of ripple marks. Grain size distribution analysis along the sloping bed revealed significant changes in the fine, non-cohesive sediment bed. It is interesting to note that the unimodal grain-size distribution was transformed to bimodal due to progressive surface waves. Moreover, strong spatial dependency was observed between the characteristics of waves and the arrangement of ripple forms. The parameters of ripples formed due to surface waves agree well with the predicted formulas. Results of near-bed turbulence due to surface waves are also reported. Furthermore, the study provides an understanding of the intricate relationships between waves, bed morphology, and changes in ripple marks. This knowledge can be applied to improve engineering practices in coastal regions.