Showing papers in "Journal of Computational Physics in 2012"

TL;DR: The framework and the adaptive algorithms enable physics-based space weather modeling and even short-term forecasting and the algorithms of BATL, the Block-Adaptive Tree Library, are described and its efficiency and scaling properties for various problems are described.

TL;DR: A basic grounding in the fundamentals of SPH is given, showing how the equations of motion and energy can be self-consistently derived from the density estimate, and how to interpret these equations using the basic SPH interpolation formulae is shown.

TL;DR: A new formulation of the boundary condition at static and moving solid walls in SPH simulations based on a local force balance between wall and fluid particles and applies a pressure boundary condition on the solid particles to prevent wall penetration.

TL;DR: The algorithm is based upon Fick's law of diffusion and shifts particles in a manner that prevents highly anisotropic distributions and the onset of numerical instability, and is validated against analytical solutions for an internal flow at higher Reynolds numbers than previously.

TL;DR: The CO5BOLD code described in this article is designed for so-called ''realistic'' simulations that take into account the detailed microphysics under the conditions in solar or stellar surface layers (equation-of-state and optical properties of the matter).

TL;DR: A stable numerical scheme for modelling multiphase flow in porous media, where the characteristic size of the flow domain is of the order of microns to millimetres, and the accuracy and stability of the numerical method are verified, which indicate the potential of the method to predict multiphases flow processes.

TL;DR: The Crank-Nicolson method is applied to a fractional diffusion equation which has the Riesz fractional derivative, and it is obtained that the method is unconditionally stable and convergent.

TL;DR: An immersed boundary method with second-order spatial accuracy is presented for fully resolved simulations of incompressible viscous flows laden with rigid particles and it is found that for spheres the choice of r"d=0.3@Dx yields second- order accuracy compared to first-order accuracy of the original method.

TL;DR: It is shown that the basic scheme is inconsistent when moving surfaces are allowed to approach closer than twice the step size, and a remedy is developed based on excluding from the force computation all surface markers whose stencil overlaps with the stencil of a marker located on the surface of a collision partner.

TL;DR: An overview of state-of-the-art modeling in special relativistic regimes, targeting strong shock-dominated flows with speeds approaching the speed of light is presented, and one such code is highlighted, MPI-AMRVAC (Message-Passing Interface-Adaptive Mesh Refinement Versatile Advection Code).

TL;DR: A new approach to Bayesian inference is presented that entirely avoids Markov chain simulation, by constructing a map that pushes forward the prior measure to the posterior measure, and demonstrates the accuracy and efficiency of the approach on nonlinear inverse problems of varying dimension.

TL;DR: This work gives a systematic method for discretizing Hamiltonian partial differential equations (PDEs) with constant symplectic structure, while preserving their energy exactly.

TL;DR: This work considers a control volume discretization with a multi-point flux approximation to model Discrete Fracture-Matrix systems for anisotropic and fractured porous media in two and three spatial dimensions and explicitly account for the fractures by representing them as hybrid cells between the matrix cells.

TL;DR: This work shows that the flexibility of the discontinuous Galerkin (dG) discretization can be fruitfully exploited to implement numerical solution strategies based on the use of elements with very general shapes, and proposes a new h-adaptive technique based on agglomeration coarsening of a fine mesh.

TL;DR: A multidimensional peridynamic formulation for transient heat-transfer which exists even at sharp corners or when the isotherms are not smooth surfaces and converges to the classical heat transfer equations in the limit of the horizon going to zero.

TL;DR: The fractional diffusion equation is discretized by the implicit finite difference scheme with the shifted Grunwald formula and the coefficient matrix possesses the Toeplitz-like structure and a multigrid method is proposed to solve the resulting system.

TL;DR: A novel mesh deformation algorithm for unstructured polyhedral meshes is developed utilizing a tree-code optimization of a simple direct interpolation method, shown to provide mesh quality that is competitive with radial basis function based methods, with markedly better performance in preserving boundary layer orthogonality in viscous meshes.

TL;DR: This paper presents an extension of this framework to construct positivity-preserving high order essentially non-oscillatory (ENO) and weighted essentiallynon-oscillsatory (WENNO) finite difference schemes for compressible Euler equations.

TL;DR: The current paper establishes the computational efficiency and accuracy of the RBF-FD method for large-scale geoscience modeling with comparisons to state-of-the-art methods as high-order discontinuous Galerkin and spherical harmonics, the latter using expansions with close to 300,000 bases.

TL;DR: The results demonstrate the feasibility of the present FSI model in accurately modeling and quantitatively evaluating flexible-wing aerodynamics of insect flapping flight in terms of the aerodynamic forces, the power consumption and the efficiency.

TL;DR: The gravitational tree-code outperforms tuned CPU code during the tree-construction and shows a performance improvement of more than a factor 20 overall, resulting in a processing rate of morethan 2.8 million particles per second.

TL;DR: The present Riemann solver provides an elegant resolution to the problem of obtaining multi-dimensionally upwinded electric fields in MHD without resorting to a doubling of the dissipation in each dimension.

TL;DR: This work presents a novel discretization scheme that adaptively and systematically builds the rapid oscillations of the Kohn-Sham orbitals around the nuclei as well as environmental effects into the basis functions.

TL;DR: A novel iterative immersed boundary (IB) method in which the body force updating is incorporated into the pressure iterations, and a wall-layer model is presented to alleviate the demanding computational requirements of a full-resolved direct numerical simulation.

TL;DR: An efficient, Bayesian Uncertainty Quantification framework using a novel treed Gaussian process model is developed and numerically demonstrate the effectiveness of the suggested framework in identifying discontinuities, local features and unimportant dimensions in the solution of stochastic differential equations.

TL;DR: One and two-dimensional numerical results provide a validation of the Asymptotic-Preserving 'all-speed' properties.

TL;DR: It is shown that the proposed method can lead to significant improvements in the definition of an optimal progress variable over conventional formulations, essentially eliminating the expert knowledge previously required in identifying such quantities.

TL;DR: A diagonal preconditioning scheme is developed that significantly improves solver performance when UPML is used and a stretched-coordinate PML results in significantly faster convergence speed than using the uniaxial PML.

TL;DR: A decimation technique for the copy from the fine to the coarse grid based on a filtering operation is introduced and it is demonstrated that to reconstruct the information, a local cubic interpolation scheme is mandatory in order to get a precision compatible with the order of accuracy of the lattice Boltzmann method.

TL;DR: A new non-overlapping domain decomposition method for the Helmholtz equation, whose effective convergence is quasi-optimal, whose improved properties result from a combination of an appropriate choice of transmission conditions and a suitable approximation of the Dirichlet to Neumann operator.