The Experts below are selected from a list of 21438 Experts worldwide ranked by ideXlab platform
Philippe Lefloch - One of the best experts on this subject based on the ideXlab platform.
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The finite volume method on a Schwarzschild background
2019Co-Authors: Shijie Dong, Philippe LeflochAbstract:We introduce a class of nonlinear hyperbolic conservation laws on a Schwarzschild black hole background and derive several properties satisfied by (possibly weak) solutions. Next, we formulate a numerical approximation scheme which is based on the finite volume methodology and takes the Curved Geometry into account. An interesting feature of our model is that no boundary conditions is required at the black hole horizon boundary. We establish that this scheme converges to an entropy weak solution to the initial value problem and, in turn, our analysis also provides us with a theory of existence and stability for a new class of conservation laws.
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Convergence of the finite volume method on a Schwarzschild background
ESAIM: Mathematical Modelling and Numerical Analysis, 2019Co-Authors: Shijie Dong, Philippe LeflochAbstract:We introduce a class of nonlinear hyperbolic conservation laws on a Schwarzschild black hole background and derive several properties satisfied by (possibly weak) solutions. Next, we formulate a numerical approximation scheme which is based on the finite volume methodology and takes the Curved Geometry into account. An interesting feature of our model is that no boundary conditions is required at the black hole horizon boundary. We establish that this scheme converges to an entropy weak solution to the initial value problem and, in turn, our analysis also provides us with a theory of existence and stability for a new class of conservation laws.
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Structure-preserving shock-capturing methods: late-time asymptotics, Curved Geometry, small-scale dissipation, and nonconservative products
2014Co-Authors: Philippe LeflochAbstract:We consider weak solutions to nonlinear hyperbolic systems of conservation laws arising in compressible fluid dynamics and we describe recent work on the design of structure-preserving numerical methods. We focus on preserving, on one hand, the late-time asymptotics of solutions and, on the other hand, the geometrical effects that arise in certain applications involving Curved space. First, we study here nonlinear hyperbolic systems with stiff relaxation in the late time regime. By performing a singular analysis based on a Chapman– Enskog expansion, we derive an effective system of parabolic type and we introduce a broad class of finite volume schemes which are consistent and accurate even for asymptotically late times. Second, for nonlinear hyperbolic conservation laws posed on a Curved manifold, we formulate geometrically consistent finite volume schemes and, by generalizing the Cockburn–Coquel–LeFloch's theorem, we establish the strong convergence of the approximate solutions toward entropy solutions.
Shijie Dong - One of the best experts on this subject based on the ideXlab platform.
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The finite volume method on a Schwarzschild background
2019Co-Authors: Shijie Dong, Philippe LeflochAbstract:We introduce a class of nonlinear hyperbolic conservation laws on a Schwarzschild black hole background and derive several properties satisfied by (possibly weak) solutions. Next, we formulate a numerical approximation scheme which is based on the finite volume methodology and takes the Curved Geometry into account. An interesting feature of our model is that no boundary conditions is required at the black hole horizon boundary. We establish that this scheme converges to an entropy weak solution to the initial value problem and, in turn, our analysis also provides us with a theory of existence and stability for a new class of conservation laws.
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Convergence of the finite volume method on a Schwarzschild background
ESAIM: Mathematical Modelling and Numerical Analysis, 2019Co-Authors: Shijie Dong, Philippe LeflochAbstract:We introduce a class of nonlinear hyperbolic conservation laws on a Schwarzschild black hole background and derive several properties satisfied by (possibly weak) solutions. Next, we formulate a numerical approximation scheme which is based on the finite volume methodology and takes the Curved Geometry into account. An interesting feature of our model is that no boundary conditions is required at the black hole horizon boundary. We establish that this scheme converges to an entropy weak solution to the initial value problem and, in turn, our analysis also provides us with a theory of existence and stability for a new class of conservation laws.
Xuguang Huang - One of the best experts on this subject based on the ideXlab platform.
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chiral kinetic theory in Curved spacetime
Physical Review D, 2019Co-Authors: Yuchen Liu, Lanlan Gao, Kazuya Mameda, Xuguang HuangAbstract:Many-body systems with chiral fermions exhibit anomalous transport phenomena originated from quantum anomalies. Based on quantum field theory, we derive the kinetic theory for chiral fermions interacting with an external electromagnetic field and a background Curved Geometry. The resultant framework respects the covariance under the U(1) gauge, local Lorentz, and diffeomorphic transformations. It is particularly useful to study the gravitational or non-inertial effects for chiral systems. As the first application, we study the chiral dynamics in a rotating coordinate and clarify the roles of the Coriolis force and spin-vorticity coupling in generating the chiral vortical effect (CVE). We also show that the CVE is an intrinsic phenomenon of a rotating chiral fluid, and thus independent of observer's frame.
Xingyu Jiang - One of the best experts on this subject based on the ideXlab platform.
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double spiral microchannel for label free tumor cell separation and enrichment
Lab on a Chip, 2012Co-Authors: Jiashu Sun, Chao Liu, Yi Zhang, Dingbin Liu, Wenwen Liu, Xingyu JiangAbstract:This work reports on a passive double spiral microfluidic device allowing rapid and label-free tumor cell separation and enrichment from diluted peripheral whole blood, by exploiting the size-dependent hydrodynamic forces. A numerical model is developed to simulate the Dean flow inside the Curved Geometry and to track the particle/cell trajectories, which is validated against the experimental observations and serves as a theoretical foundation for optimizing the operating conditions. Results from separating tumor cells (MCF-7 and Hela) spiked into whole blood indicate that 92.28% of blood cells and 96.77% of tumor cells are collected at the inner and the middle outlet, respectively, with 88.5% tumor recovery rate at a throughput of 3.33 × 107 cells min−1. We expect that this label-free microfluidic platform, driven by purely hydrodynamic forces, would have an impact on fundamental and clinical studies of circulating tumor cells.
V N Gladilin - One of the best experts on this subject based on the ideXlab platform.
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vortices on a superconducting nanoshell phase diagram and dynamics
Physical Review B, 2008Co-Authors: V N Gladilin, J Tempere, Isaac F Silvera, J T Devreese, Victor MoshchalkovAbstract:In superconductors, the search for special vortex states such as giant vortices focuses on laterally confined or nanopatterned thin superconducting films, disks, rings, or polygons. We examine the possibility of realizing giant vortex states and states with nonuniform vorticity on a superconducting spherical nanoshell due to the interplay of the topology and the applied magnetic field. We derive the phase diagram and identify where, as a function of the applied magnetic field, the shell thickness, and the shell radius, these different vortex phases occur. Moreover, the Curved Geometry allows these states or a vortex lattice to coexist with a Meissner state, on the same Curved film. We have examined the dynamics of the decay of giant vortices or states with nonuniform vorticity into a vortex lattice, when the magnetic field is adapted so that a phase boundary is crossed.
