We introduce a geometric stencil selection algorithm for Laplacian in 3D that significantly improves octant-based considered earlier. The goal of the is to choose small subset from set irregular points surrounding given point admits an accurate numerical differentiation formula. serves as influence approximation meshless finite difference methods using either polynomial or kernel-based techniqu...

We derive an implicit-explicit (IMEX) formalism for the three-dimensional Euler equations that allow a unified representation of various nonhydrostatic flow regimes, including cloud-resolving and mesoscale (flow in a 3D Cartesian domain) as well as global regimes (flow in spherical geometries). This general IMEX formalism admits numerous types of methods including single-stage multi-step method...

This paper is concerned with moving mesh finite difference solution of partial differential equations. It is known that mesh movement introduces an extra convection term and its numerical treatment has a significant impact on the stability of numerical schemes. Moreover, many implicit second and higher order schemes, such as the Crank-Nicolson scheme, will loss their unconditional stability. A ...

The axisymmetric flows with swirl or rotation were solved by a hybrid scheme with lattice Boltzmann method for the axial and radial velocities and finite-difference method for the azimuthal (or swirl) velocity and the temperature. An incompressible axisymmetric lattice Boltzmann D2Q9 model was proposed to solve the axial and radial velocities through inserting source terms into the two-dimensio...

We develop a new high order accurate time-integration technique for initial value problems. We focus on problems that originate from a space approximation using high order finite difference methods on summation-by-parts form with weak boundary conditions, and extend that technique to the timedomain. The new time-integration method is global, high order accurate, unconditionally stable and toget...

The Maxwell equations are solved by a long-stencil fourth order finite difference method over a Yee grid, in which different physical variables are located at staggered mesh points. A careful treatment of the numerical values near the boundary is introduced, which in turn leads to a “symmetric image” formula at the “ghost” grid points. Such a symmetric formula assures the stability of the bound...

This is the first in a series of two papers generated from a study on probabilistic meshless analysis of cracks. In this paper (Part I), a Galerkin-based meshless method is presented for predicting first-order derivatives of stress-intensity factors with respect to the crack size in a linear-elastic structure containing a single crack. The method involves meshless discretization of cracked stru...

Accurate solutions of the porous media equation that usually occurs in nonlinear problems of heat and mass transfer and in biological systems are obtained using a compact finite difference method in space and a low-storage total variation diminishing third-order Runge-Kutta scheme in time. In the calculation of the numerical derivatives, only a tridiagonal band matrix algorithm is encountered. ...

1 In the present study, we applied a novel mesh-free method to solve acoustic wave equation. 2 Although the conventional finite difference methods determine the coefficients of its operator 3 based on the regular grid alignment, the mesh-free method is not restricted to regular 4 arrangements of calculation points. We derive the mesh-free approach using the 5 multivariable Taylor expansion. The...