The Experts below are selected from a list of 180450 Experts worldwide ranked by ideXlab platform
Patrick Georges - One of the best experts on this subject based on the ideXlab platform.
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Laser demonstration with highly doped Yb:Gd2O3 and Yb:Y2O3 crystals grown by an original Flux Method.
Optics Letters, 2013Co-Authors: Frédéric Druon, Matias Velázquez, Philippe Veber, Sylvie Janicot, Oudomsack Viraphong, Gabriel Buse, Marwan Abdou Ahmed, Thomas Graf, Daniel Rytz, Patrick GeorgesAbstract:We present, to the best of our knowledge, the first laser demonstration of an Yb-doped Gd2O3 cubic crystal. This crystal was obtained by the Flux Method using an original borate-based solvent, which was particularly well suited to the growth of rare earth sesquioxide crystals at half the working temperature of classical growth techniques. This Flux Method is a very interesting alternative for the production of laser sesquioxide crystals, not only because it provides access to new matrices of the cubic polymorph, but also because it permits high Yb3+-doping levels for these crystals. The first laser results of two highly Yb3+-doped sesquioxides, namely Gd2O3 and Y2O3, grown by this Flux Method are presented here, including the Ti:sapphire and diode pumping configurations. Laser efficiencies and emission spectra for these two crystals were studied and compared.
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Diode-pumped lasers using highly doped Yb:Gd2O3 and Yb:Y2O3 crystals grown by the Flux Method
Advanced Solid-State Lasers Congress, 2013Co-Authors: Frédéric Druon, Matias Velázquez, Philippe Veber, Sylvie Janicot, Oudomsack Viraphong, Gabriel Buse, Marwan Abdou Ahmed, Thomas Graf, Daniel Rytz, Patrick GeorgesAbstract:Yb:Gd2O3 appears as a new crystal laser since it cannot be grown in its cubic-phase by classical growth Methods. We present laser demonstration with Yb:Gd2O3 and Yb:Y2O3 grown by the Flux Method using new solvent.
Nasser Ashgriz - One of the best experts on this subject based on the ideXlab platform.
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A spine-Flux Method for simulating free surface flows
Journal of Computational Physics, 1995Co-Authors: Farzad Mashayek, Nasser AshgrizAbstract:A new technique for the advection of liquid domains with free surfaces is developed. This technique is based on describing the liquid surface by a spine function h({alpha}, t), with {alpha} being the angle measured from one axis at time t. After discretization, the spines h{sub i}({alpha}, t) subdivide the liquid zone into conical subvolumes. The volume of each of the subvolumes is updated using the local velocities at the interface of every two neighboring subvolumes. A technique is developed to calculate the new spines based on the updated subvolumes. The Method is referred to as the spine-Flux Method (SFM) and it is implemented in a Galerkin finite element Method with penalty formulation. The problems of drop oscillation and drop collision are utilized to show the accuracy and efficiency of the technique. 28 refs., 13 figs., 1 tab.
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A height-Flux Method for simulating free surface flows and interfaces
International Journal for Numerical Methods in Fluids, 1993Co-Authors: Farzad Mashayek, Nasser AshgrizAbstract:A new technique for the numerical simulation of the free surface flows is developed. This technique is based on the finite element Method with penalty formulation, and a Flux Method for surface advection. The advection part which is completely independent of the momentum solver is based on subdividing the fluid domain into small subvolumes along one of the co-ordinate axis. The subvolumes are then used to find the height function which will later describe the free surface. The free surface of the fluid in each subvolume is approximated by a line segment and its slope is calculated using the volume of the fluid in the two neighbouring subvolumes. Later, the unidirectional volume Flux from one subvolume to its neighbouring one is calculated using the conservation laws, and the new surface line segments are reconstructed. This technique, referred to as the Height–Flux Method (HFM) is implemented to simulate the temporal instability of a capillary jet. The results of the numerical simulation well predict the experimental data. It is also shown that the HFM is computationally more efficient than the techniques which use a kinematic boundary condition for the surface advection.
Frédéric Druon - One of the best experts on this subject based on the ideXlab platform.
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Laser demonstration with highly doped Yb:Gd2O3 and Yb:Y2O3 crystals grown by an original Flux Method.
Optics Letters, 2013Co-Authors: Frédéric Druon, Matias Velázquez, Philippe Veber, Sylvie Janicot, Oudomsack Viraphong, Gabriel Buse, Marwan Abdou Ahmed, Thomas Graf, Daniel Rytz, Patrick GeorgesAbstract:We present, to the best of our knowledge, the first laser demonstration of an Yb-doped Gd2O3 cubic crystal. This crystal was obtained by the Flux Method using an original borate-based solvent, which was particularly well suited to the growth of rare earth sesquioxide crystals at half the working temperature of classical growth techniques. This Flux Method is a very interesting alternative for the production of laser sesquioxide crystals, not only because it provides access to new matrices of the cubic polymorph, but also because it permits high Yb3+-doping levels for these crystals. The first laser results of two highly Yb3+-doped sesquioxides, namely Gd2O3 and Y2O3, grown by this Flux Method are presented here, including the Ti:sapphire and diode pumping configurations. Laser efficiencies and emission spectra for these two crystals were studied and compared.
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Diode-pumped lasers using highly doped Yb:Gd2O3 and Yb:Y2O3 crystals grown by the Flux Method
Advanced Solid-State Lasers Congress, 2013Co-Authors: Frédéric Druon, Matias Velázquez, Philippe Veber, Sylvie Janicot, Oudomsack Viraphong, Gabriel Buse, Marwan Abdou Ahmed, Thomas Graf, Daniel Rytz, Patrick GeorgesAbstract:Yb:Gd2O3 appears as a new crystal laser since it cannot be grown in its cubic-phase by classical growth Methods. We present laser demonstration with Yb:Gd2O3 and Yb:Y2O3 grown by the Flux Method using new solvent.
Farzad Mashayek - One of the best experts on this subject based on the ideXlab platform.
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A spine-Flux Method for simulating free surface flows
Journal of Computational Physics, 1995Co-Authors: Farzad Mashayek, Nasser AshgrizAbstract:A new technique for the advection of liquid domains with free surfaces is developed. This technique is based on describing the liquid surface by a spine function h({alpha}, t), with {alpha} being the angle measured from one axis at time t. After discretization, the spines h{sub i}({alpha}, t) subdivide the liquid zone into conical subvolumes. The volume of each of the subvolumes is updated using the local velocities at the interface of every two neighboring subvolumes. A technique is developed to calculate the new spines based on the updated subvolumes. The Method is referred to as the spine-Flux Method (SFM) and it is implemented in a Galerkin finite element Method with penalty formulation. The problems of drop oscillation and drop collision are utilized to show the accuracy and efficiency of the technique. 28 refs., 13 figs., 1 tab.
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A height-Flux Method for simulating free surface flows and interfaces
International Journal for Numerical Methods in Fluids, 1993Co-Authors: Farzad Mashayek, Nasser AshgrizAbstract:A new technique for the numerical simulation of the free surface flows is developed. This technique is based on the finite element Method with penalty formulation, and a Flux Method for surface advection. The advection part which is completely independent of the momentum solver is based on subdividing the fluid domain into small subvolumes along one of the co-ordinate axis. The subvolumes are then used to find the height function which will later describe the free surface. The free surface of the fluid in each subvolume is approximated by a line segment and its slope is calculated using the volume of the fluid in the two neighbouring subvolumes. Later, the unidirectional volume Flux from one subvolume to its neighbouring one is calculated using the conservation laws, and the new surface line segments are reconstructed. This technique, referred to as the Height–Flux Method (HFM) is implemented to simulate the temporal instability of a capillary jet. The results of the numerical simulation well predict the experimental data. It is also shown that the HFM is computationally more efficient than the techniques which use a kinematic boundary condition for the surface advection.
Koji Morinishi - One of the best experts on this subject based on the ideXlab platform.
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Comparison of virtual Flux Method on LBM and on other Methods on a GPU
Computers & Fluids, 2013Co-Authors: Itaru Tanno, Koji Morinishi, Tomohisa Hashimoto, Takahiro Yasuda, Yoshihiro Tanaka, Nobuyuki SatofukaAbstract:Abstract The authors implemented artificial compressibility Method (ACM) with virtual Flux Method (VFM) on a GPU to simulate incompressible unsteady state flow fields around a cylinder, and lattice Boltzmann Method (LBM) on a GPU to simulate incompressible turbulent flows. In this study, unsteady flow fields around a circular cylinder were calculated by LBM with VFM. The history of the length of twin vortex behind a circular cylinder and the Strouhal number were compared with that of the other researchers; also, the speedup obtained by a GPU is shown.
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Fluid-Structure Interactive Simulation Using a Virtual Flux Method
ASME-JSME-KSME 2011 Joint Fluids Engineering Conference: Volume 1 Symposia – Parts A B C and D, 2011Co-Authors: Koji Morinishi, Tomohiro FukuiAbstract:This paper describes the resent development of a virtual Flux Method for simulating fluid-structure interaction problems. The virtual Flux Method is one of the sharp interface Cartesian grid Methods. The numerical Flux across the interface is replaced with the virtual Flux so that proper interface conditions must be satisfied there. In this study, the virtual Flux Method is applied to numerical flow simulations about reciprocating engines. The compressible Navier-Stokes equations are coupled with the equation of motion of the piston, connecting rod, and crank system. Intake and exhaust valves are lifted up and down according with the crank angle in the intake and exhaust strokes. Instead of modeling the complex fuel combustion process, a proper amount of energy is added to the Navier-Stokes equation at the beginning of each expansion stroke, to retain the four stroke engine cycle at a constant revolution rate. Initially the engine is started by starter motor force, which is added for a few seconds. The engine comes to work at the revolution rate intended after some initial transition cycles. With designing the intake and exhaust valve lift properly, intake mass and revolution rate are improved by several percent. It is confirmed that the virtual Flux Method is easily applicable to the simulation of fluid-structure interaction problems.© 2011 ASME
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Calculation by artificial compressibility Method and virtual Flux Method on GPU
Computers & Fluids, 2011Co-Authors: Itaru Tanno, Koji Morinishi, Nobuyuki Satofuka, Y. WatanabeAbstract:In this study, artificial compressibility Method and virtual Flux Method were implemented on GPUs. Because GPUs are recognized as massively parallel computers, DP-LUR was employed as time integration Method. In spite of slow convergence characteristics of DP-LUR, calculation by the coupling of DP-LUR and GPU is about 15 times faster in time than that of LU-SGS and single CPU. Virtual Flux Method, which enables to calculate flow around curved surface on the Cartesian grid is also implemented to artificial compressibility Method on GPU program, which was implemented in this study. GPU code of virtual Flux Method is about 8 times faster than CPU code.
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Validation of Virtual Flux Method for Forced Convection Flow
JSME International Journal Series B, 2006Co-Authors: Itaru Tanno, Koji Morinishi, Kenichi Matsuno, Hidetoshi NishidaAbstract:In this study, the virtual Flux Method (VFM) proposed by the authors was applied to the seamless calculation of heat fluid flow and heat conduction inside solid bodies. Flows both inside and around circular cylinders are calculated as examples. The estimated Nusselt numbers of the cylinder surfaces, which are calculated by the VFM, are compared with both numerical and experimental results obtained by other researchers. In order to show that the accuracy of the VFM is high, an exemplified seamless calculation of heat fluid flow and heat conduction inside a solid cylinder, which is an advantage of the VFM, are also performed.
