In this study we conducted a comprehensive modeling analysis to identify global trends in extreme wave energy flux (WEF) along coastlines in the 21st century under a high emission pathway (Representative Concentration Pathways 8.5). For the end of the century, results show a significant increase up to 30% in 100 year return level WEF for the majority of the coastal areas of the southern temperate zone, while in the Northern Hemisphere large coastal areas are characterized by a significant negative trend. We show that the most significant long-term trends of extreme WEF can be explained by intensification of teleconnection patterns such as the Antarctic Oscillation, El Nino–Southern Oscillation, and North Atlantic Oscillation. The projected changes will have broad implications for ocean engineering applications and disaster risk management. Especially low-lying coastal countries in the Southern Hemisphere will be particularly vulnerable due to the combined effects of projected relative sea level rise and more extreme wave activities.

Global changes of extreme coastal wave energy fluxes triggered by intensified teleconnection patterns

In this work we analyse the possibility of energy harvesting from the vibration of the environment. The investigations are performed using experimental rig, which consists of a parametrically forced pendulum and an energy harvester, and the mathematical model developed based on the experimental rig. Numerical studies focus on the oscillating motion of pendulum in 2:1 resonance and show good agreement with experimental results. We present that the energy harvesting is possible and is more efficient for shorter reduced length of the pendulum, as proved numerically and experimentally.

Energy harvesting from pendulum oscillations

https://pure.hw.ac.uk/ws/files/15631818/YA_MSSP_R2v2.pdf

Parametric pendulum based wave energy converter

Experimental versus theoretical robustness of rotating solutions in a parametrically excited pendulum: A dynamical integrity perspective

Breaking solitary wave evolution over a porous underwater step

The rotations of a parametric pendulum fitted onto a suitable floating support and forced to move vertically under the action of water waves have been studied on the basis of a dedicated wave flume laboratory experiment. An extended experimental campaign has been carried out with the aim of providing insight into the mechanics of the pendulum’s response to the wave forcing and data useful as a benchmark for available theories. A large number of time histories of the pendulum’s angular position have been collected. Rotations have been detected for different values of the frequency and of the amplitude of the excitation, showing the robustness in parameter space, and for different initial conditions, showing the robustness in phase space. This experiment, suggested by the recently developed concept of extracting energy from sea waves, constitutes preliminary experimental proof of that concept’s practical feasibility.

Experimental Rotations of a Pendulum on Water Waves

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1114&context=usnavyresearch

Comparison between the wintertime and summertime dynamics of the Misa River estuary

On the wave damping due to a permeable seabed

A campaign of experimental tests on a 2D movable-bed physical model, reproducing an Italian beach on the Adriatic Sea, has been performed in the wave flume of the “Laboratorio di Idraulica e Costruzioni Marittime” of the Universita Politecnica delle Marche (Ancona, Italy), with the aim to assess the fundamental features of various breakwater configurations to be used in a beach-defence system typical of sandy, low-coastline beaches. Three emerged and three submerged configurations of rubble-mound detached breakwaters, for beach protection, placed at different distances from the shore, were tested, as well as a free beach configuration. The short-term hydrodynamic performances of the different configurations were assessed using as forcing some typical real-life intense sea-storm conditions. Wave transmission and beach protection efficiency under various intense wave conditions were obtained and related to some dimensionless parameters, amongst which a recently introduced one, $$\chi $$
 , that combines both wave and breakwater properties. Transmission coefficients were found to be about 0.4 for emerged breakwaters and in the range 0.5–0.8 for submerged breakwaters. A net damping coefficient, defined as the wave height decay solely due to the effect of the breakwater, was measured as 0.2 for submerged breakwaters and 0.4 for the emerged ones. Further, submerged breakwaters induce an inshore mean water superelevation that increases with $$\chi $$
 , whilst it decreases in the case of emerged breakwaters. Wave transmission is well represented by existing literature relations for both emerged and submerged breakwaters. Emerged breakwaters are more protective than submerged ones, but, at the same time, are more sensitive to changes in structure dimensions or positions. This is confirmed by the analysis of the momentum flux within the nearshore region, which is much larger for the submerged breakwaters. Such structures induce large swash-zone motions and sediment transport, comparable to those occurring at an unprotected beach.

https://link.springer.com/content/pdf/10.1007%2Fs40722-016-0051-9.pdf

C. Lorenzoni

Papers

Experimental Rotations of a Pendulum on Water Waves

Comparison between the wintertime and summertime dynamics of the Misa River estuary

On the wave damping due to a permeable seabed

Experimental study of the short-term efficiency of different breakwater configurations on beach protection

Hydro- and Morpho-dynamics Induced by a Vertical Slender Pile under Regular and Random Waves