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1. TECHNICAL AND DESIGN ASPECT OF JFT-2 ICRF HEATING

Author

Paper presented by and K. Odajima

Subjects
Coupling, Engineering, Optics, business.industry, RF power amplifier, Electrical engineering, business, Radiation resistance
Abstract

Up to 820 kW of rf power is delivered to the only 460 cm 2 area of antennae with the radiation resistance about 1 ω. The radiation resistance agrees well with the strong damping model proposed by J. Adam. A plan for ridge wave guide coupling in JFT-2M is also shown.

Published
1982

2. Experimental study of bubble sweep-down in wave and current circulating tank: Part II—Bubble clouds characterization

Author

Sylvain Delacroix, Jean-Yves Billard, Grégory Germain, Benoît Gaurier, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Recherche de l'Ecole Navale (IRENAV), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM), and The authors gratefully acknowledge the DGA (the French Government Agency for Defense) and Ifremer for the financial support of this co-financed Ph.D. thesis.We also would like to thank Thomas Bacchetti and Jean-Valery Facq for their assistance in the design and set-up of these experiments, and Alcino Ferreira for the proof-reading of the final paper.

Subjects
Engineering, Environmental Engineering, Bubble, Ocean Engineering, 02 engineering and technology, Ship motions, 01 natural sciences, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], 010305 fluids & plasmas, Experimental trials, Bubble sweep-down, Optics, 0203 mechanical engineering, 0103 physical sciences, Parametric statistics, Mécanique [Sciences de l'ingénieur], business.industry, Breaking wave, Mechanics, [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph], Vortex shedding, Bow waves, 020303 mechanical engineering & transports, Bow wave, Air entrainment, Current (fluid), business, Mécanique: Mécanique des fluides [Sciences de l'ingénieur]
Abstract

In this second part, images acquired from the specific trials developed in order to study the phenomenon of bubble sweep-down are analysed. A post-processing method has been developed to analyse the two air entrainment mechanisms described in the first part, for several test configurations. Bubble clouds are described in terms of depth, area and velocity for both vortex shedding and breakingwave bubble clouds. A parametric study is also performed to calculate the influence of each test parameter on the frequency of bubble generation. It is demonstrated that the occurrence of bubble clouds is proportional to the wave height, with a considerable influence of the phase shift between waves and motions. The overall results provide new elements for the understanding and the study of the phenomenon, with the final objective of obtaining a reliable tool that facilitates the design of research vessels. The authors gratefully acknowledge the DGA (the French Government Agency for Defense) and Ifremer for the financial support of this co-financed Ph.D. thesis. We also would like to thank Thomas Bacchetti and Jean-Valery Facq for their assistance in the design and set-up of these experiments, and Alcino Ferreira for the proof-reading of the final paper.

Published
2016