A Study of Wave Dissipation Rate and Particles Velocity in Muddy Beds

Abstract

The interactions between free surface waves and layers of cohesive sediments including wave height attenuation and mud movement are of great importance in coastal and marine engineering. In this study, the results from a new analytical model were compared with those from literature experimental works and analytical models in terms of wave height dissipation rate and mud velocity. It was found that the new model provided good agreements in the case of coexisting waves and currents, while the literature model of Ng (explained in Section 2 of the text) —assuming the mud layer as a highly viscous layer with high shear rates—matched well with the experimental data for high viscosity (mud viscosity, νm = O [0.01 m2/s]). In addition, it was found that the new model is able to successfully simulate particles velocity in the presence of co-current.

An Analytical Study on Wave-Current-Mud Interaction

“…This is due to the boundary layer assumption made in this study. Shamsnia et al [34] have shown that the models with boundary layer assumptions provided better agreements with the laboratory data with higher values of mud velocities in comparison with all the other models (confirmed in the present study). However, small fluctuations-induced by the mud layer inhomogeneity-and rheological effects could not be considered by the theory.…”

“…This is because such high mud viscosities result in large boundary layer thicknesses of the mud layer that matches well with the assumptions of the proposed analytical model. (The same conclusion was provided by Shamsnia et al, [34]). It is revealed from the figure that the model provides agreements with the data in the upper layer of mud.…”

“…Despite numerous research efforts on wave-mud interactions ( [9,16,[29][30][31][32][33][34] in addition to the above-mentioned studies), very few analytical and numerical studies have been carried to formulate the effects of current on the wave-mud interactions. Nakano [35] employed an extended multi-layered fluid system to model wave-current-mud interaction.…”