Internship - Numerical Modeling And Spatial Characterisation Of Water Waves H/F - Ifremer

Join Ifremer, an ally of planetary well-being, to gain a better understanding of and better protection for the ocean.

From the abyss to the surface, from the coast to the open SEA, Ifremer is the French research institute that is wholly dedicated to the Ocean. Its teams carry out research, innovate and produce expert reports to protect the ocean, exploit its resources in a responsible manner and shares marine data.

Ifremer contributes its scientific expertise to throw light on public policies and develops solutions drawn from the ocean to meet the challenges of the ecological transition. Ifremer is the operator of France's oceanographic fleet with its shipbuilding subsidiary Genavir, and imagines, designs and deploys leading edge technological means to solve the ocean's mysteries.

Join our teams, made up of 1500 scientists and research support staff, present all along the coastal areas of France and French overseas territories.

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Keywords: water waves, stereo-video measurement, potential flow model

Context

The Laboratory of Marine Hydrodynamics (LHyMar) at Ifremer is equipped with wave basins in which scale models of offshore structures (offshore wind turbines, ships, wave energy converters) are tested under controlled wave conditions.

A reliable interpretation of these experiments requires an accurate control and characterisation of the waves. In most facilities, waves are measured using wave gauges, which record the free-surface elevation at fixed locations. The wave shape and the spatial characteristics of the wave field must be inferred from these point measurements. In several cases, direct measurements of the spatial properties of the waves would help interpreting other measurements collected during the campaign. Ifremer is currently exploring two complementary approaches to obtain spatial information on the wave field.

The first involves the use of a stereo-video system to reconstruct the free-surface elevation over a certain area. Research concerning the feasibility of this approach has been conducted at Ifremer in recent years. The measurement technique is now close to have a sufficient maturity to be considered a robust and accurate method to characterize the waves.
The second approach consists in using a digital twin of the basin to simulate the waves generated during an experiment. Potential flow solvers are attractive for this purpose because their computational cost is relatively low while they make it possible to model the non-linear propagation of the waves. They provide access to various parameters of the flow, including at locations where no direct measurements are available. Ifremer whishes to set up High-Order Spectral (HOS) simulations to support the interpretation of experimental measurements.

Mission

The intern will be in charge of modeling wave fields generated in the basin with the non-linear potential flow solver HOS-NWT. The first part of the internship will focus on assessing the accuracy of the numerical simulations by comparing the results with wave gauge
measurements. The simulations will then be compared to stereo-video measurements carried out during the PhD of Noémie Russo. Depending on the progress of the stereo-video measurements, other parameters may be extracted from the HOS simulations and compared to the wave measurements. The second part of the internship consists in assessing the potential benefits of a stereo-video system to estimate the wave spectrum. Using the HOS simulations, the intern will compare the spectrum estimations obtained from a network of virtual probes to the one obtained from virtual wave measurements over a surface.

We are seeking a highly motivated final year Master student with a strong background in fluid mechanics (mechanical engineering, applied mathematics, ...) and with a strong interest for numerical models and experimental work. Priority will be given to applicants interested in pursuing a career in research and completing a PhD in hydrodynamics (funding availability to be confirmed). Self funded interns with public servant status are also very welcome.