Surface wave propagation in coastal waters with viscoelastic boundaries

• Main Author: Dharma Sree K K
• Other Authors: Law Wing-Keung, Adrian
• Format: Theses and Dissertations
• Language: English
• Published: 2019
• Subjects: DRNTU::Engineering::Civil engineering::Water resources
• Online Access: https://hdl.handle.net/10356/106427; http://hdl.handle.net/10220/47962; https://doi.org/10.32657/10220/47962
• Institution: Nanyang Technological University

In the present study, a novel experimental approach is developed that can enable the verification of existing models for wave interactions with viscoelastic boundaries in the laboratory. Viscoelastic floating covers are prepared with the blended mixture of white oil and Polydimethylsiloxane (PDMS) material, while the bottom beds are prepared by doping glycerol with PDMS. Special curing procedures are also established to create large uniform sheets. Wave flume experiments are conducted to quantify the wave interaction with unbroken viscoelastic floating covers, viscoelastic floating segments, viscoelastic bottoms, as well as both viscoelastic top and bottom layers. It is found that the rheological properties play a key role in the modification of surface waves with respect to open water case. In particular, the viscoelastic covers behave as a low-pass filter, damping high frequency surface waves effectively. Satisfactory agreement is obtained for the dispersion relation between the experimental and theoretical results, however significant discrepancy exists for the wave attenuation. Experiments of wave interactions with fresh water ice are conducted at the University of Melbourne with several types of ice covers. Finally, wave interactions with flexible viscoelastic bottoms are studied in shallow waters, as well as a three-layer system with combined viscoelastic top and bottom boundaries.