This paper presents results of JET ITER-like wall L-mode experiments in hydrogen and deuterium (D) plasmas, dedicated to the study of the isotope dependence of ion heat transport by determination of the ion critical gradient and stiffness by varying the ion cyclotron resonance heating power deposition. When no strong role of fast ions in the plasma...
In a first moment we will be interested in the recovery of the mean-flow quantities from partial or sparse information, ranging from point-wise velocity probes to wall-pressure and friction. This will be achieved by considering the Reynolds-Averaged Navier-Stokes (RANS) equations, completed with a model, here the Spalart-Allmaras. This kind of mode...
We investigate the effect of the wall-scalar fluctuations on passive scalar turbulent fields for a moderate Reynolds number R τ = 395 and for several Prandtl numbers ranging from the very low value P r = 0.01 to the high value P r = 10 by means of DNS simulations. Several cases of plane channel flows are considered. Case I is a channel flow heated ...
Le point commun entre la voilure d’un petit drone, les pales d’une éolienne, les aubes de turbine d’un turboréacteur, la pale reculante d’un hélicoptère, ou encore les pales d’une hélice propulsant un aéronef dans la stratosphère, est le suivant : le nombre de Reynolds caractéristique de ces écoulements est faible, de sorte que la transition lamina...
This paper compares the gyrokinetic instabilities and transport in two representative JET pedestals, one (pulse 78697) from the JET configuration with a carbon wall (C) and another (pulse 92432) from after the installation of JET's ITER-like Wall (ILW). The discharges were selected for a comparison of JET-ILW and JET-C discharges with good confinem...
Geodesic acoustic modes (GAMs) may generate strong oscillations in the radial electric field and therefore are considered as a possible trigger mechanism for the L-H transition. This contribution focuses on the characterization of GAMs in JET plasmas when approaching the L-H transition aiming at understanding their possible role in triggering the t...
The elsA CFD software developed at ONERA is both a software package capitalizing the innovative results of research over time and a multipurpose tool for applied CFD and for multi-physics. elsA is intensively used by the Safran and Airbus groups and ONERA, as well as other industrial groups and research partners. This paper presents the main capabi...
In the framework of NATO task group SET 226 on turbulence mitigation techniques for OA systems, a trial was conducted in the premises of RDDC-Valcartier, using indoor and outdoor facilities in September 2016. Images data sets were collected under various turbulence conditions, both controllable (indoor) and natural (outdoor). The imagery of this tr...
The dynamical significance of vortical structures in the near field of round jets, viz. the vortex rings and the stream-wise vortices, has been known for several decades (Ho & Huerre, 1984). A fundamental understanding of their interactions , especially in turbulent jets at high Reynolds number (Re), is expected to provide an impetus to devising co...
Quasi-static aberrations in coronagraphic systems are the ultimate limitation to the capabilities of exoplanet imagers both ground-based and space-based. These aberrations - which can be due to various causes such as optics alignment or moving optical parts during the observing sequence - create light residuals called speckles in the focal plane th...
