The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Nicole Meyer-vernet - One of the best experts on this subject based on the ideXlab platform.
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The Solar Wind Energy Flux
Solar Physics, 2012Co-Authors: G. Le Chat, K. Issautier, Nicole Meyer-vernetAbstract:The solar-wind Energy Flux measured near the ecliptic is known to be independent of the solar-wind speed. Using plasma data from Helios, Ulysses, and Wind covering a large range of latitudes and time, we show that the solar-wind Energy Flux is independent of the solar-wind speed and latitude within 10%, and that this quantity varies weakly over the solar cycle. In other words the Energy Flux appears as a global solar constant. We also show that the very high speed solar-wind (VSW > 700 km/s) has the same mean Energy Flux as the slower wind (VSW < 700 km/s), but with a different histogram. We use this result to deduce a relation between the solar-wind speed and density, which formalizes the anti-correlation between these quantities.
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Study of stellar wind Energy Flux: from the Sun to Beltegeuse
AIP Conference Proceedings, 2009Co-Authors: G. Le Chat, Nicole Meyer-vernet, K. IssautierAbstract:This study examines the solar wind Energy Flux, from 17 years of Ulysses measurements at different heliolatitudes, completed by multi‐instrument observations. The solar wind Energy Flux is almost constant, nearly independant on wind speed and solar activity. We then compare the Energy Flux of the Sun to the stellar wind Fluxes, in addition to the luminosity Fluxes, from young stars to supergiants. A share processus of origin and acceleration of the main‐sequence stars and cool giants’ winds is suggested. T‐Tauri stars’winds show a possible result of an accretion powered wind.
G. Le Chat - One of the best experts on this subject based on the ideXlab platform.
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The Solar Wind Energy Flux
Solar Physics, 2012Co-Authors: G. Le Chat, K. Issautier, Nicole Meyer-vernetAbstract:The solar-wind Energy Flux measured near the ecliptic is known to be independent of the solar-wind speed. Using plasma data from Helios, Ulysses, and Wind covering a large range of latitudes and time, we show that the solar-wind Energy Flux is independent of the solar-wind speed and latitude within 10%, and that this quantity varies weakly over the solar cycle. In other words the Energy Flux appears as a global solar constant. We also show that the very high speed solar-wind (VSW > 700 km/s) has the same mean Energy Flux as the slower wind (VSW < 700 km/s), but with a different histogram. We use this result to deduce a relation between the solar-wind speed and density, which formalizes the anti-correlation between these quantities.
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Study of stellar wind Energy Flux: from the Sun to Beltegeuse
AIP Conference Proceedings, 2009Co-Authors: G. Le Chat, Nicole Meyer-vernet, K. IssautierAbstract:This study examines the solar wind Energy Flux, from 17 years of Ulysses measurements at different heliolatitudes, completed by multi‐instrument observations. The solar wind Energy Flux is almost constant, nearly independant on wind speed and solar activity. We then compare the Energy Flux of the Sun to the stellar wind Fluxes, in addition to the luminosity Fluxes, from young stars to supergiants. A share processus of origin and acceleration of the main‐sequence stars and cool giants’ winds is suggested. T‐Tauri stars’winds show a possible result of an accretion powered wind.
Johan Larsson - One of the best experts on this subject based on the ideXlab platform.
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turbulent Energy Flux generated by shock homogeneous turbulence interaction
Journal of Fluid Mechanics, 2016Co-Authors: Russell Quadros, Krishnendu Sinha, Johan LarssonAbstract:High-speed turbulent flows with shock waves are characterized by high localized surface heat transfer rates. Computational predictions are often inaccurate due to the limitations in modelling of the unclosed turbulent Energy Flux in the highly non-equilibrium regions of shock interaction. In this paper, we investigate the turbulent Energy Flux generated when homogeneous isotropic turbulence passes through a nominally normal shock wave. We use linear interaction analysis where the incoming turbulence is idealized as being composed of a collection of two-dimensional planar vorticity waves, and the shock wave is taken to be a discontinuity. The nature of the postshock turbulent Energy Flux is predicted to be strongly dependent on the angle of incidence of the incoming waves. The Energy Flux correlation is also decomposed into its vortical, entropy and acoustic contributions to understand its rapid non-monotonic variation behind the shock. Three-dimensional statistics, calculated by integrating two-dimensional results over a prescribed upstream Energy spectrum, are compared with available data from direct numerical simulations. A detailed budget of the governing equation is also considered in order to gain insight into the underlying physics.
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Turbulent Energy Flux generated by shock/homogeneous-turbulence interaction
Journal of Fluid Mechanics, 2016Co-Authors: Russell Quadros, Krishnendu Sinha, Johan LarssonAbstract:High-speed turbulent flows with shock waves are characterized by high localized surface heat transfer rates. Computational predictions are often inaccurate due to the limitations in modelling of the unclosed turbulent Energy Flux in the highly non-equilibrium regions of shock interaction. In this paper, we investigate the turbulent Energy Flux generated when homogeneous isotropic turbulence passes through a nominally normal shock wave. We use linear interaction analysis where the incoming turbulence is idealized as being composed of a collection of two-dimensional planar vorticity waves, and the shock wave is taken to be a discontinuity. The nature of the postshock turbulent Energy Flux is predicted to be strongly dependent on the angle of incidence of the incoming waves. The Energy Flux correlation is also decomposed into its vortical, entropy and acoustic contributions to understand its rapid non-monotonic variation behind the shock. Three-dimensional statistics, calculated by integrating two-dimensional results over a prescribed upstream Energy spectrum, are compared with available data from direct numerical simulations. A detailed budget of the governing equation is also considered in order to gain insight into the underlying physics.
K. Issautier - One of the best experts on this subject based on the ideXlab platform.
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The Solar Wind Energy Flux
Solar Physics, 2012Co-Authors: G. Le Chat, K. Issautier, Nicole Meyer-vernetAbstract:The solar-wind Energy Flux measured near the ecliptic is known to be independent of the solar-wind speed. Using plasma data from Helios, Ulysses, and Wind covering a large range of latitudes and time, we show that the solar-wind Energy Flux is independent of the solar-wind speed and latitude within 10%, and that this quantity varies weakly over the solar cycle. In other words the Energy Flux appears as a global solar constant. We also show that the very high speed solar-wind (VSW > 700 km/s) has the same mean Energy Flux as the slower wind (VSW < 700 km/s), but with a different histogram. We use this result to deduce a relation between the solar-wind speed and density, which formalizes the anti-correlation between these quantities.
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Study of stellar wind Energy Flux: from the Sun to Beltegeuse
AIP Conference Proceedings, 2009Co-Authors: G. Le Chat, Nicole Meyer-vernet, K. IssautierAbstract:This study examines the solar wind Energy Flux, from 17 years of Ulysses measurements at different heliolatitudes, completed by multi‐instrument observations. The solar wind Energy Flux is almost constant, nearly independant on wind speed and solar activity. We then compare the Energy Flux of the Sun to the stellar wind Fluxes, in addition to the luminosity Fluxes, from young stars to supergiants. A share processus of origin and acceleration of the main‐sequence stars and cool giants’ winds is suggested. T‐Tauri stars’winds show a possible result of an accretion powered wind.
Ivan Pšenčík - One of the best experts on this subject based on the ideXlab platform.
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Energy Flux in viscoelastic anisotropic media
Geophysical Journal International, 2006Co-Authors: Vlastislav Červený, Ivan PšenčíkAbstract:SUMMARY We study properties of the Energy-Flux vector and other related Energy quantities of homogeneous and inhomogeneous time-harmonic P and S plane waves, propagating in unbounded viscoelastic anisotropic media, both analytically and numerically. We propose an algorithm for the computation of the Energy-Flux vector, which can be used for media of unrestricted anisotropy and viscoelasticity, and for arbitrary homogeneous or inhomogeneous plane waves. Basic part of the algorithm is determination of the slowness vector of a homogeneous or inhomogeneous wave, which satisfies certain constraints following from the equation of motion. Approaches for determination of a slowness vector commonly used in viscoelastic isotropic media are usually difficult to use in viscoelastic anisotropic media. Sometimes they may even lead to non-physical solutions. To avoid these problems, we use the so-called mixed specification of the slowness vector, which requires, in a general case, solution of a complex-valued algebraic equation of the sixth degree. For simpler cases, as for SH waves propagating in symmetry planes, the algorithm yields simple analytic solutions. Once the slowness vector is known, determination of Energy Flux and of other Energy quantities is easy. We present numerical examples illustrating the behaviour of the Energy-Flux vector and other Energy quantities, for homogeneous and inhomogeneous plane P, SV and SH waves.
