|
|
|
|
|
| Mallat, Bachar; Germain, Gregory; Billard, Jy; Gaurier, Benoit; Facq, Jean-valery; Bacchetti, Thomas. |
| The bubble sweep-down phenomenon around oceanographic research vessels generates acoustic disturbances. This phenomenon has affected the acoustic surveys for many years and is still a significant issue. The reason is that neither towing tank trials nor numerical simulations are able to properly address this phenomenon. We proposed a specific experimental protocol in a wave and current circulating tank allowing a 3D visualization of the bubble sweep-down phenomenon around two ship models with different bow geometries. Visualisations and Particle Image Velocimetry (PIV) measurement results both obtained in the bow vicinity of the two ship models are presented in this paper. These results allow a better representation of the phenomenon compare to previous... |
| Tipo: Text |
|
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00412/52332/53117.pdf |
| |
|
| |
|
|
| Delacroix, Sylvain; Germain, Gregory; Billard, Jean-yves; Gaurier, Benoit; Facq, Jean-valery; Bacchetti, Thomas. |
| The bubble sweep-down phenomenon around the hull of scientific vessels leads to a disruption of the acoustic waves emitted by the sonars, and a loss of productivity during the acoustic surveys. Numerical or experimental tools used to study this phenomenon still have limitations, mainly due to scale effects on bubbles generation. An innovative method in a circulating tank, using numerical simulations and a motions generator, has been developed. Two mechanisms of air entrainment have been described, as well as the influence of waves characteristics and turbulence on bubbles generation. |
| Tipo: Text |
|
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00247/35807/34321.pdf |
| |
|
|
| Kervella, Youen; Germain, Gregory; Gaurier, Benoit; Facq, Jean-valery; Bacchetti, Thomas. |
| Les futures zones d’implantation des parcs hydroliens en mer sont caractérisées par des courants de forte intensité et des taux de turbulence importants. Cette turbulence de l’écoulement est susceptible d’altérer le comportement des hydroliennes, à la fois en termes de production d’énergie mais aussi de fatigue structurelle. Afin de déterminer l’influence de la turbulence ambiante sur les effets d’interaction entre hydroliennes, des essais expérimentaux ont été effectués dans un bassin à houle et courant, sur des maquettes d’hydroliennes tri-pales à axe horizontal, régulées en vitesse de rotation. Les interactions entre trois hydroliennes placées sur deux rangées (deux hydroliennes sur la rangée amont et une sur la rangée aval, ou inversement) ont été... |
| Tipo: Text |
Palavras-chave: Énergie marine; Hydroliennes; Turbulence; Effets d'interaction; Essais expérimentaux.. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00212/32342/30782.pdf |
| |
|
| |
|
|
| Germain, Gregory; Maganga, Fabrice; Gaurier, Benoit; Facq, Jean-valery; Bacchetti, Thomas; Pinon, Grégory; Rivoalen, Elie; Etancelin, Jean-matthieu. |
| This paper presents experimental results of tests carried out in order to investigate the hydrodynamics of marine current turbines and to build an experimental database used to validate the numerical developments conducted to characterize the flow perturbations induced by marine current turbines. For that purpose, we used a tri-bladed horizontal axis turbine. Particular attention is paid to the flow characteristic effects (velocity gradient, flow orientation, flow turbulence intensity level) on the performance of a 0.70 m diameter turbine. The main interest is to study how the far wake decays downstream, in order to estimate the effect produced in downstream turbines. Analyses are made from Laser Doppler Velocimeter measurements (velocity and turbulence... |
| Tipo: Text |
|
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00021/13263/10310.pdf |
| |
|
|
|
