Post-doctoral position: Seagrass restoration project in the Berre lagoon - efficiency and optimisation of a wave absorption system

Context

The Berre Lagoon (France) is one of the largest Mediterranean lagoons (155 km²). It's a shallow semi-confined ecosystem (mean depth 6.5 m) connected to the Mediterranean Sea via the Caronte channel. It receives freshwater from two main rivers and from Saint-Chamas EDF hydroelectric power plant. As a transitional system, there are many interactions between marine water, freshwater and meteorological forcings.

In the late 19th and early 20th centuries, the lagoon bottom was covered by a very extensive Zostera sp. meadows. These meadows perform numerous functions like stabilizing the sea bottom, providing food and habitats for other marine organisms. But, because of eutrophication, organic pollution through increasing agriculture and urbanization in river catchments, over-sedimentation, Zostera sp. meadows declined in the Berre Lagoon. Transplantation experiments have been achieved, with some positive but always limited results (survival, expansion). This could be due to strong hydrodynamic stresses (currents, waves): uprooting and damages on roots and leaves could prevent their expansion.

Scientific work has already been achieved. Seagrass characteristics have been monitored in situ. Hydrodynamics and sedimentology in a bay of the lagoon has been studied during a PhD work at the CEREGE (European Center for Research and Teaching Geosciences and Environment, France) (Paquier, 2014). A hydrodynamic numerical model (waves – currents coupled model considering effect of vegetation on hydrodynamics) has also been developed in a post-doctoral work at the LNHE-LHSV Lab (National Laboratory for Hydraulics and Environment EDF R&D and Hydraulics Laboratory Saint Venant, France) to better understand hydrodynamic processes involved.

As a result of these studies, temporary use of artificial seagrass mats could be considered as a soft engineering solution to reduce wave and induce favorable hydrodynamic conditions for natural seagrass expansion. The post-doctoral position is a preliminary step for a possible future mat (artificial seagrass) deployment as a demonstrator: it will assess the efficiency of such a system in real site conditions. The final objective of this work is to propose demonstrator specifications in terms of material, sizing, positioning, etc.

Objectives

A numerical « waves – 3D currents » coupled model (TOMAWAC and TELEMAC-3D softwares) covering a Berre lagoon specific area exists and will be used during this research work. It calculates waves and currents characteristics resulting from hydrodynamic forcings and takes into account vegetation effect on hydrodynamics (implemented in the model by means of its geometrical characteristics and a drag coefficient).

The proposed research work is both experimental (wave propagation experiments in a flume) and numerical (waves and 3D currents modelling). The 3 main tasks are:

1. First step of the study is based on numerical modelling. Wave generation and propagation in the studied area will be simulated for a period of about 3 years. Simulation results will be analyzed and the wave regime characterized in order to define the features of the waves for the flume experiments.
2. Experimental part of the study will rely on LNHE physical modelling facilities and skills. First, the postdoctoral researcher will contribute to identification of some materials that can be used as artificial vegetal mats, depending on technical and environmental specifications. The candidate will also contribute to the definition of an experimental protocol (methodology, metrology...). Experiments in a wave flume will then be carried out with one or several types of artificial mats. The aim is to study their effect on waves attenuation depending on different parameters (materials geometric characteristics, water depth, wave characteristics...). Based on the measurements, the quantification of a "drag coefficient" will be used to estimate ability of the tested materials to attenuate waves.
3. The numerical model will be used to compute hydrodynamics in the area of interest when considering artificial seagrass mats installed on the lagoon bottom. These mats are supposed to limit hydrodynamic stresses in some target areas in order to favor natural seagrass development. Numerical simulations will contribute to artificial seagrass mats sizing and positioning optimization and thus technical specifications for a possible in situ demonstrator deployment will be proposed.

 Conditions

• 12 months fixed-term job.
• PhD required.
• Skills: Hydrodynamics, numerical modelling.
• An experience in experimental field would be appreciated as well as some knowledge on Fortran programming.

Laboratory

Laboratoire Hydraulique Saint-Venant LHSV
6, Quai Watier – 78400 Chatou (west suburbs from Paris)
France
RER A – Rueil-Malmaison station
http://www.saint-venant-lab.fr/saint-venant

Contact

Nathalie Durand (LNHE – EDF R&D)

Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

Phone: (+33)1.30.87.77.50

Postdoc position in numerical modelling of coastal particulate transport

The Hydraulics Division of the KU Leuven Department of Civil Engineering offers a 2 year postdoc position (2017-2018) in the framework of the EU JPI Oceans Microplastics project WEATHER-MIC (http://www.jpi-oceans.eu/weather-mic/about). The task consists of the set-up of a 3-dimensional numerical model to simulate the transport, fate and dispersion of microplastic particles released from water treatment plant overflows in the Oslo Fjord and the Himmerfjärden Bay (Stockholm).

During this period, the postdoc will also contribute to the BELSPO STEREOIII project Proba4Coast (comparison of simulated SPM data with remote sensing images for the Belgian coastal area), the BELSPO BRAIN.be project INID67 (numerical simulation of SPM in the Belgian coastal area) and the VLAIO funded SBO project CREST (Climate resilient Coast – www.crestproject.be) (numerical simulation of beach erosion for the Belgian coast).

In all these case the same TELEMAC modelling system will be used. Different new process modules (especially for flocculation and biofilm formation) will have to be developed, implemented and tested.

The research is a continuation of ongoing work, i.e. much preparatory work (including the set-up of the hydrodynamic models) is mostly done. The selected postdoc will collaborate with other researchers within the KU Leuven Sediment Mechanics research group, as well as with TELEMAC users and developers in Belgium, France and the UK.

Profile

The candidate holds a PhD degree in civil, hydraulic or coastal engineering, oceanography or mechanical engineering (specialized in CFD). The master degree does not need to be in the same discipline. The ideal candidate has:

• theoretical knowledge of the physics of fluid flow, turbulence, waves and particulate (or sediment) transport
• experience in numerical modelling of fluid flow (computational fluid dynamics, preferably applied to 2D and 3D hydraulics and morphodynamics)
• experience in the use of the TELEMAC system (TELEMAC, TOMAWAC and SISYPHE) and knowledge of its code and numerical techniques
• experience in CFD code development and theoretical knowledge of numerical modelling
• experience in coding in FORTRAN.

Candidatures (including motivation letter, CV, diploma transcripts and relevant publications) and requests for further information can be sent to: Prof. Erik TOORMAN Hydraulics Division, Department of Civil Engineering, KU Leuven Kasteelpark Arenberg 40 (box 2448), B-3001 Heverlee, Belgium E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it., Tel. +32 16 32 16 59, Fax +32 16 32 19 89

Post-doctoral position on parametric shape optimisation in hydraulics

The Saint-Venant Hydraulics Laboratory (Chatou, France) seeks to fill a 18 month post-doctoral position in the field of parametric shape optimisation for hydraulic and environmental problems, with the following main topics:

• Robust shape and topology optimisation applied to river and/or coastal applications
• Identification of optimal zones and/or boundaries to improve the efficiency or to minimise costs while guaranteeing the design constrains of hydraulic structures (e.g. water intakes) subject to different forcing effects

The aim of this post-doctoral position is to develop an efficient numerical tool based on TELEMAC system (widely used open-source code www.opentelemac.org) able to deliver optimal shape design for hydraulic engineering applications. The work will be mainly based on the implementation, improvement and development of computational methods capable to solve optimisation problems based on derivative-free and gradient algorithms. These algorithms will be first verified and validated on simplified configurations and then applied to selected industrial cases. Successful applicants should, by the start of the appointment, have a Ph.D., or equivalent experience in Applied Mathematics, Applied Physics, Computer Sciences or Mechanical/Civil Engineering. Experience of high performance numerical computing and/or programming are highly desirable. The researcher will be employed by Ecole des Ponts ParisTech. Salary and benefits will be commensurate with qualifications and experience.

About Saint-Venant laboratory and the host research team

The Saint-Venant Hydraulics Laboratory is a joint research laboratory between Ecole des Ponts ParisTech (ENPC), Electricité de France R&D (EDF R&D) and Cerema. This gives it a unique position in the field of applied fluid mechanics, at the interface between academy and industry. The Saint-Venant laboratory is actively engaged in fundamental and applied research, and its research activities are organized along three main themes: (i) Waves and marine hazards, (ii) Modeling and simulation of free-surface flows, (iii) Sediment transport and morphodynamics. The laboratory has access to a unique variety of facilities, such as the 8000 m2 of experimental facilities and the development of high-performance CFD models for environmental flows and transport processes, including the opensource Telemac-Mascaret modelling system (http://www.opentelemac.org). The laboratory is located on the EDF Lab site in Chatou (France), about 15 km from Paris downtown. More information about our laboratory can be found at: http://www.saint-venant-lab.fr

How to apply

Applicants should send to Drs. Riadh Ata (This email address is being protected from spambots. You need JavaScript enabled to view it.) and Cedric Goeury (This email address is being protected from spambots. You need JavaScript enabled to view it.) a CV and a cover letter. All applications completed by May 15th 2017 will receive full consideration, but candidates are urged to submit all required material as soon as possible. Applications will be accepted until the position is filled. For more information, please contact Dr. Riadh Ata, EDF R&D and Saint-Venant Laboratory, This email address is being protected from spambots. You need JavaScript enabled to view it. and Dr. Cedric Goeury, EDF R&D, This email address is being protected from spambots. You need JavaScript enabled to view it.. Deadline for application: 15th May 2017