Bottom mud transport due to water waves

The interactions between surface water waves and a soft mud bottom have been investigated in this study through mathematical modeling, laboratory experiments and model applications to field observations.; Based on the viscoelastic theory and laboratory tests, a constitutive model has been developed to describe mud rheology. The model simulates observed strain creep and stress relaxation responses, and it is shown that the viscoelastic properties of mud depend strongly on wave frequency. The developed model is reduced to the commonly used but more restrictive Voigt model at comparatively high frequencies. Such frequencies however are of uncommon interest in relevant coastal environments.; A second order hydrodynamic model has been developed to examine important wave-mud interactions. The water column is considered to be viscid and mud to be viscoelastic. Due to the second order consideration, the usual restriction of a small wave amplitude is removed in the model. In conjunction with the developed constitutive model, the hydrodynamic model predicts surface wave attenuation, mud acceleration and mass transport. These predictions have been compared with laboratory experiments, and agreements found to be satisfactory. To further demonstrate the applicability of the model, it has been applied to predict wave attenuation over coastal mudbanks. Comparison with measured wave spectra shows reasonable agreement. Wave-related data from Lake Okeechobee, Florida have also been simulated with a reasonable degree of success.; Based on a force balance, a theoretical expression for the water-mud interface set-up has been developed. The predicted equilibrium interface profile generally agrees with that measured in the laboratory. Further, a hypothesis regarding the time-evolution of the interface has been examined as a mechanism to explain the observed cross-shore motion of the above mentioned coastal mudbanks.