Description du sujet de thèse

The PhD topic is part of the MSCA Doctoral Network BETTER (Building the nExT generaTion of marine Eco-friendly wind faRm) which is coordinated by CNR (Italy).
Description of the MSCA DN BETTER project :
BETTER aims to form a new generation of professional experts on Offshore Wind Farming (OWF). This team will address the noticeable knowledge and technological gap that exists in comprehending how marine ecosystems respond to the ongoing and anticipated extensive expansion of OWFs and how to incorporate these considerations into the optimised design. The BETTER consortium is formed by experts in geology, oceanography, marine ecology, marine biology, geotechnical engineering, computation modelling, offshore engineering, underwater acoustics, data science and mathematics across 7 European countries (Italy, Norway, Netherlands, Germany, France, Portugal and UK). The whole network comprises 15 academic partners and 3 industry partners.
Description of the PhD topic :
Installation of bottom-fixed foundation piles is known to generate high levels of noise in the water column, that affect marine mammals even at great distances to the piles, and energetic seismic waves of different kinds (bulk waves, interface waves) inducing seabed vibrations. Recent studies have suggested that the particle motion of interface waves has potential deleterious effects on species living near to or on the seabed. However, while noise abatement systems such as, e.g., bubble curtains are considered quite efficient for mitigating noise impacts on marine mammals, to date it is not clear whether these solutions are also suitable for strongly attenuating seabed vibrations, and therefore preserving marine life in the vicinity of the seabed. In recent years, studies of noise propagation and seabed vibrations induced by pile driving have been conducted in specific marine environments , and therefore, the results obtained cannot be generalized to environments with different properties. Indeed, as their frequency content is low, acoustic waves in water and seismic waves interact in a complex way, and these interactions strongly depend on both physical and geometrical properties of the marine environment.
The proposed PhD topic aims to broaden the knowledge of noise propagation and seabed vibrations induced by pile driving by investigating the wave interaction between the water column and the seabed, according to various marine environments with different physical and geometrical properties, including the presence of sedimentary basins. The methodology will be mostly based on full-wave numerical modeling using a spectral-element method and High-Performance Computing (HPC), and considering a realistic source model of pile driving. The numerical results will be validated against real acoustic and seismic data. According to the various marine environments considered, the goal will be to evaluate the distance to the pile where seismic waves/seabed vibrations no longer pose a potential threat to marine species, and to propose appropriate recommendations for noise/vibration mitigation.
Skills required
The candidate should :
- hold a M.Sc. diploma in Acoustics and/or Geosciences and/or Applied Mathematics, preferably in some relation to acoustic and/or elastic waves, and/or partial differential equations;
- have an excellent knowledge of the English language;
- be familiar with numerical computing languages;
- be eager to expand his knowledge in numerical modeling and ocean acoustics.

Contexte de travail

The successful candidate will be hosted by the Laboratory of Mechanics and Acoustics (LMA) which is a joint research laboratory (CNRS/Aix-Marseille Univ./Centrale Marseille). The laboratory hosts about 130 people including 45 researchers/professors and 40 PhD/post-doctoral fellows. LMA develops research activities related to solid mechanics and acoustics, and is structured into 3 research teams: Materials & Structures, Sounds, Waves & Imaging. The successful candidate will be hosted by the Waves & Imaging team, and will work in close collaboration with the “Marine acoustics & Seismic Imaging” group which has a renowned expertise in underwater acoustics and seismo-acoustics, numerical modeling of wave propagation, and seismic imaging. The successful candidate will also collaborate with other PhD students within the BETTER network. The “Marine acoustics & Seismic Imaging” group has an easy access to modern and powerful facilities (large-scale parallel computers) for high-performance simulations. This group is also involved in European projects and has many international collaborations.
In accordance with MSCA regulations for Doctoral Candidates, the successful candidate will receive a monthly gross salary which includes living and mobility allowances. If applicable, additional allowances may be granted. Family allowance will be implemented if the candidate has or acquires family obligations during the project (i.e. marriage or relationship with recognized equivalent status to a marriage, dependent children who are actually being maintained by the candidate). For candidates with disabilities certified by a competent national authority, the salary may also comprise a special needs allowance, if not already funded from another source (e.g. social security or health insurance). The special needs allowance contributes to the additional costs for the acquisition of special needs items and services.

Informations complémentaires

The position includes travels and short secondments in The Netherlands, Italy, Switzerland, Portugal and France.
Eligibility and mobility criteria
To be eligible for the positions, applicants :
- must not yet have been awarded a doctoral degree at the date of their recruitment in the project,
- are required to undertake transnational mobility (i.e., move from one country to another) when taking up their appointment. Candidates must not have resided or carried out their main activity (work, studies, etc.) in France for more than 12 months in the 3 years immediately before the recruitment date. Compulsory national service, short stays such as holidays, and time spent as part of a procedure for obtaining refugee status under the Geneva Convention are not taken into account. Candidates may be required to provide supporting documentation proving their place(s) of residence or work during the previous 3 years.
The eligibility and mobility of the candidates will be determined at the time of their recruitment in the project.