Numerical Study of Plasma-edge Turbulence and Velocity Shear

Numerical Study of Plasma-edge Turbulence and Velocity Shear PDF Author: G. Manfredi
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ISBN:
Category :
Languages : en
Pages :

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Numerical Study of Plasma-edge Turbulence and Velocity Shear

Numerical Study of Plasma-edge Turbulence and Velocity Shear PDF Author: G. Manfredi
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Numerical study of plasma-edge turbulence nd velocity shear

Numerical study of plasma-edge turbulence nd velocity shear PDF Author: G. Manfredi
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Stress corrosion cracking can potentially cause fuel failures at circumferential ridges in the sheath. finite element computer codes elestres and feast are used to calculate two-dimensional, axisymmetric, elastic-plastic sheath stresses at and near the circumferential ridges. the level of stresses is given by the fuel design (such as pellet/sheath diameters, pellet length, pellet density) and by the operating conditions (such as power history). the accuracy, convergence, and cost of the stress calculations, however, are determined by the discretization used in the calculations: the number of nodes in the finite element mesh; the shape of the individual finite elements; the pattern into which the finite elements are arranged; and the size of the calculation-steps into which the power history is subdivided. in this study, we determined the discretization that gives a reasonable compromise of accuracy, convergence, and cost for the stress calculations. the highest accuracy is obtained by using triangular finite elements of aspect ratios close to one, and assembling them into hexagonal patterns. to caputure the stress gradients, five nodes are required across the sheath wall at the ridge, but two nodes are sufficient near the midplane of the pellet. the resulting mesh contains about 200 nodes and about 300 finite elements. calculation-steps of 6 kw/m provide a convergent solution, with a factor of two margin against numerical divergence. with the above arrangement, feast needs about 2.4 seconds on a cdc/cyber 175 computer to calculate sheath stresses per calculation-step. six radial nodes at the ridge would double the computing cost. decreasing the size of the calculation-steps means more calculations are needed to analyze a given power history, giving a linear increase in computing cost.

Numerical Study of Velocity Shear Stabilization of 3D and Theoretical Considerations for Centrifugally Confined Plasmas and Other Interchange-Limited Fusion Concepts

Numerical Study of Velocity Shear Stabilization of 3D and Theoretical Considerations for Centrifugally Confined Plasmas and Other Interchange-Limited Fusion Concepts PDF Author:
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ISBN:
Category :
Languages : en
Pages :

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We studied the feasibility of resonantly driving GAMs in tokamaks. A numerical simulation was carried out and showed the essential features and limitations. It was shown further that GAMs can damp by phase-mixing, from temperature gradients, or nonlinear detuning, thus broadening the resonance. Experimental implications of this were quantified. Theoretical support was provided for the Maryland Centrifugal Experiment, funded in a separate grant by DOE. Plasma diamagnetism from supersonic rotation was established. A theoretical model was built to match the data. Additional support to the experiment in terms of numerical simulation of the interchange turbulence was provided. Spectra from residual turbulence on account of velocity shear suppression were obtained and compared favorably to experiment. A new drift wave, driven solely by the thermal force, was identified.

Energy Transfer and Dissipation in Plasma Turbulence

Energy Transfer and Dissipation in Plasma Turbulence PDF Author: Yan Yang
Publisher: Springer
ISBN: 9811381496
Category : Science
Languages : en
Pages : 134

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Book Description
This book revisits the long-standing puzzle of cross-scale energy transfer and dissipation in plasma turbulence and introduces new perspectives based on both magnetohydrodynamic (MHD) and Vlasov models. The classical energy cascade scenario is key in explaining the heating of corona and solar wind. By employing a high-resolution hybrid (compact finite difference & WENO) scheme, the book studies the features of compressible MHD cascade in detail, for example, in order to approximate a real plasma cascade as “Kolmogorov-like” and to understand features that go beyond the usual simplified theories based on incompressible models. When approaching kinetic scales where plasma effects must be considered, it uses an elementary analysis of the Vlasov–Maxwell equations to help identify the channels through which energy transfer must be dissipated. In addition, it shows that the pressure–strain interaction is of great significance in producing internal energy. This analysis, in contrast to many other recent studies, does not make assumptions about wave-modes, instability or other specific mechanisms responsible for the dynamics – the results are direct consequences of the Vlasov–Maxwell system of equations. This is an important step toward understanding dissipation in turbulent collisionless plasma in space and astrophysics.

Numerical Simulation

Numerical Simulation PDF Author: Mykhaylo Andriychuk
Publisher: BoD – Books on Demand
ISBN: 9535107496
Category : Computers
Languages : en
Pages : 662

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Book Description
Numerical Simulation - from Theory to Industry is the edited book containing 25 chapters and divided into four parts. Part 1 is devoted to the background and novel advances of numerical simulation; second part contains simulation applications in the macro- and micro-electrodynamics. Part 3 includes contributions related to fluid dynamics in the natural environment and scientific applications; the last, fourth part is dedicated to simulation in the industrial areas, such as power engineering, metallurgy and building. Recent numerical techniques, as well as software the most accurate and advanced in treating the physical phenomena, are applied in order to explain the investigated processes in terms of numbers. Since the numerical simulation plays a key role in both theoretical and industrial research, this book related to simulation of many physical processes, will be useful for the pure research scientists, applied mathematicians, industrial engineers, and post-graduate students.

Plasma and Fluid Turbulence

Plasma and Fluid Turbulence PDF Author: A. Yoshizawa
Publisher: CRC Press
ISBN: 1420033697
Category : Science
Languages : en
Pages : 459

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Book Description
Theory and modelling with direct numerical simulation and experimental observations are indispensable in the understanding of the evolution of nature, in this case the theory and modelling of plasma and fluid turbulence. Plasma and Fluid Turbulence: Theory and Modelling explains modelling methodologies in depth with regard to turbulence phenomena a

Numerical Simulation of Turbulence in the Presence of Shear

Numerical Simulation of Turbulence in the Presence of Shear PDF Author: Shlomo Shaanan
Publisher:
ISBN:
Category : Eddy flux
Languages : en
Pages : 152

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Theoretical and Numerical Study of Anomalous Turbulent Transport in Plasmas

Theoretical and Numerical Study of Anomalous Turbulent Transport in Plasmas PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 36

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Book Description
Theoretical and computational analysis of particle transport in a plasma turbulence was carried out. Particle behavior was investigated by test particle simulations in different types of plasma turbulence, including drift wave turbulence, ion acoustic turbulence and Langmuir turbulence. Resonance broadening in real space around mode rational surface was confirmed in drift wave turbulence. Nonresonant interaction of waves and particles were studied in ion acoustic turbulence. Resonance broadening in velocity space was found as a result of non-Markovian process in Langmuir turbulence. A semiclassical quantum plasma approach was also applied to plasma turbulence. Some instabilities in toroidal geometry were studied as eigen value problems.

Experimental and Numerical Study of Turbulence in Fusion Plasmas Using Reflectometry Synthetic Diagnostics

Experimental and Numerical Study of Turbulence in Fusion Plasmas Using Reflectometry Synthetic Diagnostics PDF Author: Georgiy Zadvitskiy
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Computation and Comparison of Efficient Turbulence Models for Aeronautics — European Research Project ETMA

Computation and Comparison of Efficient Turbulence Models for Aeronautics — European Research Project ETMA PDF Author: Alain Dervieux
Publisher: Springer Science & Business Media
ISBN:
Category : Mathematics
Languages : en
Pages : 604

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This volume contains contributions to the BRITE-EURAM 3rd Framework Programme ETMA and extended articles of the TMA-Workshop. It focusses on turbulence modelling techniques suitable to use in typical flow configurations, with emphasis on compressibility effects and inherent unsteadiness. These methodologies are applied to the Navier-Stokes equations, involving various turbulence modelling levels from algebraic to RSM. Basic turbulent flows in aeronautics are considered; mixing layers, wall-flows (flat-plate, backward-facing step, ramp, bump), and more complex configurations (bump, aerofoil). A critical assessment of the turbulence modelling performances is offered, based on previous results and on the experimental data-base of this research programme. The ETMA results figure in the data-base constituted by all partners and organized by INRIA