The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Urs Achim Wiedemann - One of the best experts on this subject based on the ideXlab platform.
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nearly Isentropic Flow at sizeable η s
Physics Letters B, 2018Co-Authors: Aleksi Kurkela, Urs Achim WiedemannAbstract:Abstract Non-linearities in the harmonic spectra of hadron–nucleus and nucleus–nucleus collisions provide evidence for the dynamical response to azimuthal spatial eccentricities. Here, we demonstrate within the framework of transport theory that even the mildest interaction correction to a picture of free-streaming particle distributions, namely the inclusion of one perturbatively weak interaction (“one-hit dynamics”), will generically give rise to all observed linear and non-linear structures. We further argue that transport theory naturally accounts within the range of its validity for realistic signal sizes of the linear and non-linear response coefficients observed in azimuthal momentum anisotropies with a large mean free path of the order of the system size in peripheral ( ∼ 50 % centrality) PbPb or central pPb collisions. As a non-vanishing mean free path is indicative of non-minimal dissipation, this challenges the perfect fluid paradigm of ultra-relativistic nucleus–nucleus and hadron–nucleus collisions.
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Nearly Isentropic Flow at sizeable η/s
Physics Letters B, 2018Co-Authors: Aleksi Kurkela, Urs Achim WiedemannAbstract:Abstract Non-linearities in the harmonic spectra of hadron–nucleus and nucleus–nucleus collisions provide evidence for the dynamical response to azimuthal spatial eccentricities. Here, we demonstrate within the framework of transport theory that even the mildest interaction correction to a picture of free-streaming particle distributions, namely the inclusion of one perturbatively weak interaction (“one-hit dynamics”), will generically give rise to all observed linear and non-linear structures. We further argue that transport theory naturally accounts within the range of its validity for realistic signal sizes of the linear and non-linear response coefficients observed in azimuthal momentum anisotropies with a large mean free path of the order of the system size in peripheral ( ∼ 50 % centrality) PbPb or central pPb collisions. As a non-vanishing mean free path is indicative of non-minimal dissipation, this challenges the perfect fluid paradigm of ultra-relativistic nucleus–nucleus and hadron–nucleus collisions.
Aleksi Kurkela - One of the best experts on this subject based on the ideXlab platform.
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nearly Isentropic Flow at sizeable η s
Physics Letters B, 2018Co-Authors: Aleksi Kurkela, Urs Achim WiedemannAbstract:Abstract Non-linearities in the harmonic spectra of hadron–nucleus and nucleus–nucleus collisions provide evidence for the dynamical response to azimuthal spatial eccentricities. Here, we demonstrate within the framework of transport theory that even the mildest interaction correction to a picture of free-streaming particle distributions, namely the inclusion of one perturbatively weak interaction (“one-hit dynamics”), will generically give rise to all observed linear and non-linear structures. We further argue that transport theory naturally accounts within the range of its validity for realistic signal sizes of the linear and non-linear response coefficients observed in azimuthal momentum anisotropies with a large mean free path of the order of the system size in peripheral ( ∼ 50 % centrality) PbPb or central pPb collisions. As a non-vanishing mean free path is indicative of non-minimal dissipation, this challenges the perfect fluid paradigm of ultra-relativistic nucleus–nucleus and hadron–nucleus collisions.
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Nearly Isentropic Flow at sizeable η/s
Physics Letters B, 2018Co-Authors: Aleksi Kurkela, Urs Achim WiedemannAbstract:Abstract Non-linearities in the harmonic spectra of hadron–nucleus and nucleus–nucleus collisions provide evidence for the dynamical response to azimuthal spatial eccentricities. Here, we demonstrate within the framework of transport theory that even the mildest interaction correction to a picture of free-streaming particle distributions, namely the inclusion of one perturbatively weak interaction (“one-hit dynamics”), will generically give rise to all observed linear and non-linear structures. We further argue that transport theory naturally accounts within the range of its validity for realistic signal sizes of the linear and non-linear response coefficients observed in azimuthal momentum anisotropies with a large mean free path of the order of the system size in peripheral ( ∼ 50 % centrality) PbPb or central pPb collisions. As a non-vanishing mean free path is indicative of non-minimal dissipation, this challenges the perfect fluid paradigm of ultra-relativistic nucleus–nucleus and hadron–nucleus collisions.
Paul Glaister - One of the best experts on this subject based on the ideXlab platform.
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Conservative upwind differencing for Isentropic Flows
Mathematical and Computer Modelling, 2003Co-Authors: Paul GlaisterAbstract:In a recent paper [1], a number of numerical schemes for the shallow water equations based on a conservative linearization were analysed. The current paper seeks to generalize this work to include the Isentropic Flow equations. This is an important first step in generalizing such schemes to encompass compressible Flows of a real gas. Such Flows are governed by the Euler equations with a nonideal equation of state as a general expression for the pressure. A similar expression for the pressure occurs in the Isentropic Flow equations.
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Shock capturing for steady, supersonic, two-dimensional Isentropic Flow
International Journal for Numerical Methods in Fluids, 1991Co-Authors: Paul GlaisterAbstract:A finite difference scheme is presented for the solution of the two-dimensional equations of steady, supersonic, Isentropic Flow. The scheme incorporates numerical characteristic decomposition, is shock-capturing by design and incorporates space marching as a result of the assumption that the Flow is wholly supersonic in at least one space dimension. Results are shown for problems involving oblique hydraulic jumps and reflection from a wall.
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An Isentropic Flow algorithm with body fitted meshes
Computers & Mathematics with Applications, 1991Co-Authors: Paul GlaisterAbstract:An efficient algorithm based on flux difference splitting is presented for the solution of the three-dimensional equations of Isentropic Flow in a generalised coordinate system, and with a general convex gas law. The scheme is based on solving linearised Riemann problems approximately and in more than one dimension incorporates operator splitting. The algorithm requires only one function evaluation of the gas law in each computational cell. The scheme has good shock capturing properties and the advantage of using body-fitted meshes. Numerical results are shown for Mach 3 Flow of air past a circular cylinder. Furthermore, the algorithm also applies to shallow water Flows by employing the familiar gas dynamics analogy.
Xiaohong Wang - One of the best experts on this subject based on the ideXlab platform.
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Numerical study of underwater shock wave by a modified method of characteristics
Journal of Applied Physics, 2014Co-Authors: Chengjiao Zhang, Xiaohong WangAbstract:This paper introduces a modified method of characteristics as well as its application to simulation of a 1D spherical underwater explosion. To check the performance of the modified method, corresponding codes for computer calculation are developed to simulate the underwater explosion problem which is a typical Isentropic Flow problem. In applying the modified method, shock wave is calculated based on the Rankine-Hugoniot conservation relations. Artificial viscosity is not used in the simulation, and thus the corresponding influence of artificial viscosity is not introduced into the simulation. The work is mainly focused on underwater shock wave and secondary shock wave. The results simulated with the modified method are compared with other results from experiment and AUTODYN software, and the comparisons show that the modified method results are coincident with the experimental results in acceptable accuracy. Compared with the AUTODYN results, the modified method results are consistent with the experimental results better in far field. The formation and propagation of the secondary shock and the position of the gas-water interface are well captured, and the variations in Flow field can be obtained. On the basis of the comparisons, it can be demonstrated that the modified method of characteristics can be applied to the simulation of 1D Isentropic Flow problems effectively.
David Harris - One of the best experts on this subject based on the ideXlab platform.
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A high resolution scheme for Eulerian gas-solid two-phase Isentropic Flow
Journal of Computational Physics, 2006Co-Authors: Justin Hudson, David HarrisAbstract:Numerical solutions of the equations governing two-phase Isentropic Flow of a solid granular material dispersed in a gas are investigated. Both the dispersed and continuous phases are treated as continua and an Eulerian description of the Flow is adopted. We present an inviscid model with a general pressure term from which a number of variant models can be obtained. A high resolution scheme is presented to obtain numerical approximations of the equations in each of the models. We investigate whether the chosen numerical scheme is suitable for the equations governing the models and use the numerical results to obtain quantitative and qualitative insight into the predictions of each of the models. Three test cases, new to the literature, are considered, and the numerical results compared.
