Clotilde Nové-Josserand’s PhD defense. Converting wave energy from fluid–elasticity interactions

PhD defense on October 1st, 2018, 2:30pm, at the PMMH meeting room (Sorbonne Université, Barre Cassan, Bât. A 1er Étage, 7 Quai Saint Bernard, 75005 Paris).

Converting wave energy from fluid–elasticity interactions

Understanding the mechanisms involved in wave-structure interactions is of high interest for the development of efficient wave energy harvesters as well as for coastal management. In this thesis, we study the interactions of surface waves with a model array of slender flexible structures, in view of developing an efficient system for both attenuating and harvesting wave energy. The presented results are based around experimental investigations, by means of small scale facilities, in which the spatial arrangement of the flexible objects is the key parameter of study. The model array is first characterised by evaluating the role played by various parameters (configuration, flexibility, wave frequency) on the energy distribution in our system. Following these first observations, an interference model is then developed in order to describe the observed global effects of the array on both the wave field and the blade dynamics, based on known local parameters of a unit item of the array. This model then serves as a tool for exploring many possible array configurations, in order to determine the optimal choice regarding both the attenuation and the absorption of the imposed waves. A final experimental study is presented, in which the key results from the interference model are evaluated and the underlying principles of array optimisation are identified.

Jury:

Médéric Argentina (Institut de Physique de Nice) Rapporteur
Olivier Doaré (ENSTA ParisTech) Rapporteur
Aurélien Babarit (École Centrale de Nantes) Examinateur
Delphine Doppler (Université Claude Bernard Lyon 1) Examinatrice
Sandra Lerouge (Université Paris Diderot) Examinatrice
William Megill (Hochschule Rhein-Waal) Examinateur
Gaële Perret (Université du Havre) Examinatrice
Ramiro Godoy-Diana (ESPCI Paris) Directeur de thèse
Benjamin Thiria (ESPCI Paris) Directeur de thèse

Surface wave energy absorption by a partially submerged bio-inspired canopy

Surface wave energy absorption by a partially submerged bio-inspired canopy
C. Nové-Josserand, F. Castro Hebrero, L.-M. Petit, W. Megill, R. Godoy-Diana & B. Thiria
Bioinspiration & Biomimetics 13 036006 (2018)
[doi:10.1088/1748-3190/aaae8c]
PDF file

Aquatic plants are known to protect coastlines and riverbeds from erosion by damping waves and fluid flow. These flexible structures absorb the fluid-borne energy of an incoming fluid by deforming mechanically. In this paper we focus on the mechanisms involved in these fluid-elasticity interactions, as an efficient energy harvesting system, using an experimental canopy model in a wave tank.We study an array of partially-submerged flexible structures that are subjected to the action of a surface wave field, investigating in particular the role of spacing between the elements of the array on the ability of our system to absorb energy from the flow. The energy absorption potential of the canopy model is examined using global wave height measurements for the wave field and local measurements of the elastic energy based on the kinematics of each element of the canopy. We study different canopy arrays and show in particular that flexibility improves wave damping by around 40%, for which half is potentially harvestable.