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A potential flow based flight simulator for an underwater glider ArchiMer
Phoemsapthawee, Surasak; Le Boulluec, Marc; Laurens, Jean-marc; Deniset, Francois.
Underwater gliders are recent innovative types of autonomous underwater vehicles (AUVs) used in ocean exploration and observation. They adjust their buoyancy to dive and to return to the ocean surface. During the change of altitude, they use the hydrodynamic forces developed by their wings to move forward. Their flights are controlled by changing the position of their centers of gravity and their buoyancy to adjust their trim and heel angles. For better flight control, the understanding of the hydrodynamic behavior and the flight mechanics of the underwater glider is necessary. A 6-DOF motion simulator is coupled with an unsteady potential flow model for this purpose. In some specific cases, the numerical study demonstrates that an inappropriate stabilizer...
Tipo: Text Palavras-chave: Underwater glider; Hydrodynamics; Potential flow; 6DOF; Newton-Euler equation; AUVs.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00171/28227/26480.pdf
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Barge pour environnements type Bresil : essais en bassin ArchiMer
Le Boulluec, Marc; Maisondieu, Christophe; Du Plessix, Guillaume; Cordeau, Cyril.
drilling capability designed by SAIPEM for oil production offshore Brazil or area with equivalent environmental conditions. A central moon-pool is surrounded by a system of walls and columns above an immersed pontoon. An upper deck is situated above the water line. Sea water can flow between walls and columns above the pontoon. The aim of wave tank experiments is to validate the preliminary sea keeping calculations and study the free surface effects inside the moon-pool and above the pontoon.
Tipo: Text Palavras-chave: Hydrodynamique; Essais en bassin; Houle; Surélévations; Diffraction; Radiation; Moon-pool.
Ano: 2005 URL: http://archimer.ifremer.fr/doc/00170/28169/26403.pdf
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Benefits of using a spectral hindcast database for wave power extraction assessment ArchiMer
Maisondieu, Christophe; Le Boulluec, Marc.
When considering deployment of wave energy converters at a given site, it is of prime importance from both a technical and an economical point of view to accurately assess the total yearly energy that can be extracted by the given device. Especially, to be considered is the assessment of the efficiency of the device over the widest span of the sea-states spectral bandwidth. Hence, the aim of this study is to assess the biases and errors introduced on extracted power classically computed using spectral data derived from analytical functions such as a JONSWAP spectrum, compared to the power derived using actual wave spectra obtained from a spectral hindcast database.
Tipo: Text Palavras-chave: Wave energy; Wave spectra; Hindcast; Resource assessment.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00347/45799/45445.pdf
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Caractérisation d'effets de sillages rencontrés en milieu offshore ArchiMer
Gaurier, Benoit; Germain, Gregory; Le Boulluec, Marc; Giry, Eric; Fontaine, E..
The interactions between several cylinders placed in close proximity are the subject of many studies, because of the strong repeated loads that they create on these structures. For flexible or mobile structures, the wake effects can produce large amplitudes motions. These displacements can be higher than those considered during the lock-in of a single cylinder, to reach several diameters. Depending the initial spacing, they lead sometimes to clashes with potentially high intensity, between the cylinders. To better understand these phenomena, an experimental study was carried out, bearing on the interaction between two models of tensioning buoy supporting hybrid risers. After checking that the models used were able to correctly reproduce the movements...
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Ano: 2007 URL: http://archimer.ifremer.fr/doc/00023/13439/10447.pdf
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Control Strategies for Floating Offshore Wind Turbine: Challenges and Trends ArchiMer
Salic, Tom; Charpentier, Jean Frédéric; Benbouzid, Mohamed; Le Boulluec, Marc.
The offshore wind resource has huge energy potential. However, wind turbine floating structures have to withstand harsh conditions. Strong wind and wave effects combine to generate vibrations, fatigue, and heavy loads on the structure and other elements of the wind turbine. These structural problems increase maintenance requirements and risk of failure, while reducing availability and energy production. Another challenge for wind energy is to reduce production costs in order to be competitive with other alternatives. From the control point of view, the objective of lowering costs can be achieved by operating the turbine close to its optimum point of operation under partial load, guaranteeing reliability by reducing structural loads and regulating the power...
Tipo: Text Palavras-chave: Wind energy; Floating offshore wind turbine; Control; State of art review.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00588/69991/67899.pdf
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Etude expérimentale d'un système de conversion de l'énergie des vagues exploitant les oscillations d'une masse d'eau contenue dans un tube en u ArchiMer
Fonseca, Nuno; Pessoa, Joao; Ribeiro E Silva, Sergio; Le Boulluec, Marc; Ohana, Jeremy.
The paper presents the results of an experimental program with a scaled model of the UGEN wave energy converter (WEC). This concept has been developed by IST (Instituto Superior Técnico) based on a floating body with a U tank filled with water. The amount of water accounts for 40% of the floater displacement. The sway, heave and roll motion of the floating body coupled to the water oscillating in the U tube induce an oscillating air flow on the upper part of the U tank from one branch to the other through a circular tube. The aim of the device is to capture the air flow energy through a turbine. The natural period of the water in the U tank (circa 1.25 s) and of the resulting floating body natural rolling period (circa 1.9 s) are separated in such a way...
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Ano: 2010 URL: http://archimer.ifremer.fr/doc/00170/28173/26407.pdf
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Etude expérimentale pour l'optimisation des performances d'une plage d'amortissement parabolique ArchiMer
Le Boulluec, Marc; Kimmoun, Olivier; Molin, Bernard.
An optimisation study was run before rebuilding the damping beach of the Ifremer Ocean Engineering Basin. Trials were conducted at a ¼ geometrical scale at Ecole Centrale de Marseille in a wave tank reproducing the original performance of the beach. A series of modifications was studied : incidence, device between the beach and the adjacent wall, porosity. Porosity was shown as the most efficient tool to enhance the beach absorption and full scale measurements revealed that the resulting damping coefficient was less than 10 % for all usual periods and amplitudes.
Tipo: Text Palavras-chave: Hydrodynamique; Essais en bassin; Houle; Réflexion; Amortissement; Plage; Hydrodynamics; Wave tank testing; Reflection; Damping beach.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/00170/28170/26404.pdf
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Evaluation experimentale des caracteristiques hydrodynamiques de plaques anti-pilonnement ArchiMer
Le Boulluec, Marc; Le Roux, Dominique; Ohana, Jeremy; Ivanoff, Nicolas; Chalony, Sebastien; Tancray, Aurelien; Scolan, Yves-marie.
Tank tests of circular horizontal plates, solid and porous, are conducted in forced heave motion and under the action of incident waves in fixed configuration. Hydrodynamic coefficients for added inertia and drag are identified from experimental results. Their dependency with the Keulegan Carpenter number and other parameters is evaluated. The acquired data open the possibility of additional investigations and assessment with numerical calculations in viscous fluid (CFD).
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Ano: 2016 URL: http://archimer.ifremer.fr/doc/00392/50350/51046.pdf
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Experimental and numerical results on VIV and WIO ArchiMer
Gaurier, Benoit; Germain, Gregory; Le Boulluec, Marc; Giry, Eric; Fontaine, Emmanuel.
Vortex-Induced Vibrations (VIV) are well-known and related to the majority of cylindrical structures subjected to strong winds or currents. The VIV limit the lifetime of the structure because they increase the forces and so the fatigue. When several structures of this kind are put together in close interaction, the wake effects (Wake Induced Oscillations - WIO) sometimes involve strong instabilities. If these structures are flexible or mobile, oscillations of several diameters can be observed and collisions can occur ([4] & [6]). Such structures are widespread in the oil industry where the extraction of oil in deep water can be done by means of risers. In some cases, risers are connected to a floating support called FPSO (Floating Production Storage...
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Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-6584.pdf
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Générateur de vent pour la modélisation physique de structures offshore ArchiMer
Ohana, Jeremy; Le Boulluec, Marc; Peron, Eric; Klinghammer, Christian; Tancray, Aurelien; Mansuy, Emmanuel.
Les modèles numériques associant les efforts hydrodynamiques et aérodynamiques sur les structures flottantes nécessitent d’être validés expérimentalement. Pour cela de nombreux bassins d’essais s’équipent de générateurs de vent. Nous présentons ici une description technique de la soufflerie du bassin de l’Ifremer de Brest, ainsi que les mesures de vents à vitesse constante, variable puis cisaillée issue de la campagne de qualification menée en janvier 2014.
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Ano: 2014 URL: http://archimer.ifremer.fr/doc/00233/34390/32783.pdf
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Infragravity waves and moored floating structures ArchiMer
Klinghammer, Christian; Prevosto, Marc; Le Boulluec, Marc; Perignon, Yves.
Up to this day, design recommendations or practices for floating structures, such as DNVs RP-C205 and F205 for example, do not account for the existence of low frequency free Infragravity (IG) waves. These are low-frequency water waves which represent an additional excitation for (moored) floating structures. In this study, the influence of free IG waves on moored floating structures response is investigated and compared to second-order low-frequency wave forces, as the standard low frequency excitation, for two selected important free IG events in 2013 and 2014 at the SEM-REV (Site d'Experimentation En Mer - Récupération de l'Energie des Vagues) test site near Le Croisic, Pays-de-la-Loire, France. The wave forces and motion response for two example...
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Ano: 2015 URL: http://archimer.ifremer.fr/doc/00384/49584/50094.pdf
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Interaction houle-courant en bathymétrie variable via une approche de type boussinesq ArchiMer
Guinot, Florent; Le Boulluec, Marc; Rey, Vincent.
Modeling wave-current interaction needs a method combining accurate kinematics and reasonable computing efforts. Refined waves kinematics are described by a Boussinesq-type approach allowing a variable bathymetry. This method is adapted to take current effects into account. Results on Doppler shift, waves blocking and velocity profile are reported in a twodimensional case.
Tipo: Text Palavras-chave: Interaction houle-courant; Approche de Boussinesq; Profil de vitesse; Wave-current interaction; Boussinesq approach; Velocity profile.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/00170/28172/26406.pdf
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Interaction houle-courant par profondeur finie : impact sur la cinématqiue ArchiMer
Rey, Vincent; Guinot, Florent; Le Boulluec, Marc.
The aim of this large scale basin experiment on wave current interactions was a better understanding of vertical velocity profiles changes due to progressive surface waves. The instrumentation deployed including wave gauges, pressure sensors and current meters allowed precise measurements along the basin. In particular, the effect of waves on the homogenization of vertical profile was measured, and the effect of current on the underestimate of wave height from bottom mounted pressure sensors was demonstrated. However, the current flow without wave was bi-dimensional and weakly sheared, and no study on the current instability as observed in previous experiment could be achieved.
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Ano: 2007 URL: http://archimer.ifremer.fr/doc/00170/28171/26405.pdf
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Modélisation expérimentale et numérique d'un tourbillon de vidange avec injection en régime super-critique ArchiMer
Fourestier, Gaspard; Santagostini, Timothee; Le Boulluec, Marc; Magaldi, Philippe; Scolan, Yves-marie.
One type of low head hydropower plant is studied. This solution, based on a bathtub vortex, is called the gravitational vortex hydropower. It consists in a turbine placed at the center of the vortex which harvests the vortex kinetic energy. As a first step, the bathtub vortex is studied without the turbine, in the supercritical flow regime. An experimental campaign is carried out to study this bathtub vortex. Water heights are measured using acoustic sensors in seven points in the tank. A laser Doppler velocimetry device is deployed to measure the velocities in three planes in the water flow. Simulations are performed using OpenFOAM 2.2.2 with a two phase approach using the volume of fluid method (solver interFoam). First simulations are performed without...
Tipo: Text Palavras-chave: Tourbillon de vidange; InterFoam; Vélocimétrie laser; Bathtub vortex; InterFoam; Laser Doppler velocimetry.
Ano: 2017 URL: https://archimer.ifremer.fr/doc/00410/52190/55231.pdf
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Modélisation expérimentale et numérique d'un tourbillon de vidange avec injection en régime supercritique ArchiMer
Fourestier, Gaspard; Santagostini, Timothée; Le Boulluec, Marc; Magaldi, Philippe; Scolan, Yves-marie.
One type of low head hydropower plant is studied. This solution, based on a bathtub vortex, is called the gravitational vortex hydropower. It consists on a turbine placed at the center of the vortex which allows to harvest the kinetic energy [1]. As a first step, the bathtub vortex is studied without the turbine, in the supercritical flow regime. A numerical model has been performed using OpenFOAM 2.2.2. A two phases approach, using the volume of fluid method has been chosen. Simulations are mostly done without any modelling of turbulent phenomena (laminar model). In order to validate the numerical approach, an experimental campaign is carried out. The experimental data are compared qualitatively and quantitatively to the values extracted from the...
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Ano: 2016 URL: http://archimer.ifremer.fr/doc/00392/50354/51053.pdf
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Numerical and experimental modeling of offshore wind energy capture: Application to reduced scale model testing ArchiMer
Doisenbant, Gonzalo; Le Boulluec, Marc; Scolan, Y-m; Guyot, M..
Horizontal axis wind turbines installed on board floating supports stand among the principles of offshore wind energy capture. This document describes the experimental device and methodology for analyzing the performance of a reduced scale model of a 12 MW horizontal axis floating wind turbine. The particularity of this turbine is that it is mounted on a floater conceived according to Eolink’s concept, where several masts connect the nacelle with the floater. The tests are performed at Ifremer’s ocean basin. For that purpose, a wind generator and a model at scale 1:50 are developed. The experimental results are compared with numerical estimations obtained with the blade element momentum method.
Tipo: Text Palavras-chave: Offshore wind energy; Model testing; Horizontal axis wind turbine (HAWT); Floating bodies; Pitch angle; Blade element momentum.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00435/54639/56082.pdf
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Numerical model validation for mooring systems: Method and application for wave energy converters ArchiMer
Harnois, V.; Weller, Sam D.; Johanning, L.; Thies, P. R.; Le Boulluec, Marc; Le Roux, Dominique; Soule, Veronique; Ohana, Jeremy.
The design of wave energy mooring systems is challenging: overdesign incurs a significant cost penalty, underdesign may lead to a premature failure and incorrect design could reduce the power production. Consequently, compliant mooring systems are being developed for wave energy applications. This paper presents tank test results for a scale model of the buoy and mooring used at the SouthWest Mooring Test Facility (SWMTF), an offshore facility developed to conduct long-term sea trials for wave energy device moorings. A compliant three leg catenary mooring system using Nylon ropes in the water column is investigated. Preliminary static, quasi-static, decay, regular and irregular wave tests were conducted on the 1:5 scale model, using the Ifremer basin in...
Tipo: Text Palavras-chave: Wave energy converter; Tank tests; Numerical model; Highly dynamic mooring system; Fibre rope.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00233/34375/35785.pdf
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Second order loads characterization in shallow water with a slope bottom ArchiMer
Rouault, Marie Christine; Molin, Bernard; Le Boulluec, Marc; Petrie, François.
An experimental campaign was previously reported on the slow-drift motion of a rectangular barge moored in irregular beam seas. The 24 m long false bottom of the basin is raised and inclined at a slope of 5% from 1.05m below the free surface to 0.15m above (see figure 1). The barge is moored in different water depths (from 54 cm to 21 cm). The measured slowdrift component of the sway motion is compared with state of the art calculations based on Newman approximation. The principal results are, for the beam sea configuration: - at 54 cm depth: good agreement between the experimental results and the Newman simulation - at 21 cm depth: the Newman calculation overpredicts the forces. When the flat bottom set-down contribution is added, the calculated value is...
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Ano: 2012 URL: http://archimer.ifremer.fr/doc/00170/28174/26408.pdf
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Stabilisation du roulis d'un navire par les mouvements d'un fluide avec surface libre contenu dans une cuve ArchiMer
Le Boulluec, Marc; Ohana, Jeremy; Chalony, Sebastien; Tancray, Aurelien; Le Gall, Clément; Fourestier, Gaspard; Santagostini, Timothée; Ercolanelli, Julien; Cueff, Quentin; Raoul, Samuel.
A method for reducing the roll of a ship consists in placing a tank whose liquid content is animated by free surface sloshing motions. The dynamic coupling with the vessel is studied experimentally at reduced model in a test tank. Numerical modeling under perfect fluid and viscous fluid assumptions make it possible to approach the measured responses.
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Ano: 2016 URL: http://archimer.ifremer.fr/doc/00392/50352/51049.pdf
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Wave and turbulence measurements at a tidal energy site ArchiMer
Filipot, Jean-francois; Prevosto, Marc; Maisondieu, Christophe; Le Boulluec, Marc; Thomson, Jim.
This work presents the analysis of wave and turbulence measurements collected at a tidal energy site. A new method is introduced to produce more consistent and rigorous estimations of the velocity fluctuations power spectral densities. An analytical function is further proposed to fit the observed spectra and could be input to the numerical models predicting power production and structural loading on tidal turbines. Another new approach is developed to correct for the effect of the Doppler noise on the high frequencies power spectral densities. The analysis of velocity time series combining wave and turbulent contributions demonstrates that the turbulent motions are coherent throughout the water column, rendering the wave coherence-based methods not...
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Ano: 2015 URL: http://archimer.ifremer.fr/doc/00254/36537/35074.pdf
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