Physics

  2010 AUG 31 - (VerticalNews.com) -- According to recent research from Curitiba, Brazil, "We present an efficient numerical methodology for the 31) computation of incompressible multi-phase flows described by conservative phase-field models We focus here on the case of density matched fluids with different viscosity (Model H) The numerical method employs adaptive mesh refinements (AMR) in concert with an efficient semi-implicit time discretization strategy and a linear, multi-level multigrid to relax high order stability constraints and to capture the flow's disparate scales at optimal cost. ...read more

  2010 AUG 31 - (VerticalNews.com) -- According to recent research from the United States, "This paper presents a third-order and fourth-order finite-volume method for solving the shallow-water equations on a non-orthogonal equiangular cubed-sphere grid Such a grid is built upon an inflated cube placed inside a sphere and provides an almost uniform grid point distribution The numerical schemes are based on a high-order variant of the Monotone Upstream-centered Schemes for Conservation Laws (MUSCL) pioneered by van Leer. In each cell the reconstructed left and right states are either obtained via a dimension-split piecewise-parabolic method or a piecewise-cubic reconstruction The reconstructed states then serve as Input to an approximate Riemann solver that determines the numerical fluxes at two Gaussian quadrature points along the cell boundary The use of multiple quadrature points renders the resulting flux high-order. ...read more

  2010 AUG 31 - (VerticalNews.com) -- "An adaptive implicit-explicit scheme for Direct Numerical Simulation (DNS) and Large-Eddy Simulation (LES) of compressible turbulent flows on unstructured grids is developed The method uses a node-based finite-volume discretization with Summation-by-Parts (SBP) property, which, in conjunction with Simultaneous Approximation Terms (SAT) for imposing boundary conditions, leads to a linearly stable semi-discrete scheme The solution is marched in time using an Implicit-Explicit Runge-Kutta (IMEX-RK) time-advancement scheme," scientists in the United States report ...read more