Water surface elevations and near-bed velocity measurements over ultra-rough bed surfaces subjected to regular waves

Abstract: Ultra-rough oceanic surfaces, such as oyster reefs, bare the potential to effectively attenuate wave energy due to increased bed roughness compared to the surrounding sea floor. The high bed roughness is influenced by the size and shape of the individual roughness elements, e.g., the oyster shells. To effectively employ ultra-rough oceanic surfaces as a nature-based solution in coastal protection, a currently unavailable detailed understanding of the frictional wave energy dissipation processes is necessary. This dataset provides the results of an experimental study in which primitive surrogate models of ultra-rough oceanic surfaces were subjected to regular waves. Three shapes of roughness elements (bluntly-shaped (semicircle), sharp-edged (lamella), and combinations thereof (mix)) with two spacings between elements, λ (1: λ1 = 0.10 m; 2: λ2 = 0.20 m), have been tested, resulting in six ultra-rough bed surface configurations (abbreviated as: SC1, SC2, L1, L2, M1, and M2) and a reference configuration (REF) without roughness elements. The surrogate models (total length of 16 m) were subjected to regular waves with a constant water depth d = 0.7 m, a constant wave height H = 0.147 m, and varying wave periods T = 1.5 s; 2.0 s 2.5 s; 3.0 s. The dataset comprises water surface elevations η and near-bed instantaneous velocity components, ui, vi, and wi, in x, y, and z directions, respectively, measured along the tested ultra-rough bed surfaces.