We analyze the consistency, stability, and convergence of an hp discontinuous Galerkin spectral element method of Kopriva [J. Comput. Phys., 128 (1996), pp. 475–488] and Kopriva, Woodruff, and Hussaini [Internat. J. Numer. Methods Engrg., 53 (2002), pp. 105–122]. The analysis is carried out simultaneously for acoustic, elastic, coupled elastic-acoustic, and electromagnetic wave propagation. Our...

A new method is developed to simulate the fully coupled motion involving an ellipsoidal particle and the ambient fluid. This method essentially reduces a two-phase flow problem into a single-phase fluid flow problem. The momentum exchange at the interface between the particle and the fluid is computed in a spectral element method. To validate this method and demonstrate the accuracy of the resu...

We present a simple new approach to the solution of a wide class of spectral and resonance problems on infinite domains with regular ends, including those found in the study of quantum switches, waveguides, and acoustic scatterers. Our algorithm is part analytical and part numerical and is essentially a combination of four classical approaches (domain decomposition, boundary elements, finite el...

In this paper an efficient analytical method is presented for calculating the eigenvalues of special matrices related to finite element meshes (FEMs) with regular topologies. In the proposed method, a skeleton graph is used as the model of a FEM. This graph is then considered as the Cartesian product of its generators. The eigenvalues of the Laplacian matrix of the entire graph are then easily ...

The paper presents a time-domain method for computation of sound radiation from aircraft engine sources to the far-field. The effects of nonuniform flow around the aircraft and scattering of sound by fuselage and wings are accounted for in the formulation. Our approach is based on the discretization of the inviscid flow equations through a collocation form of the Discontinuous Galerkin spectral...

Spectral partitioning methods use the Fiedler vector—the eigenvector of the second-smallest eigenvalue of the Laplacian matrix—to find a small separator of a graph. These methods are important components of many scientific numerical algorithms and have been demonstrated by experiment to work extremely well. In this paper, we show that spectral partitioning methods work well on bounded-degree pl...

The Computational Singular Perturbation (CSP) method, developed by Lam and Goussis [Twenty-Second Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, 1988, pp. 931–941], is a commonly-used method for finding approximations of slow manifolds in systems of ordinary differential equations (ODEs) with multiple time scales. The validity of the CSP method was established fo...

In this work we will discuss the solution of an initial value problem of parabolic type. The main objective is to propose an alternative method of solution, one not based on finite difference or finite element or spectral methods. The aim of the present paper is to investigate the application of the Adomian decomposition method for solving the Fokker–Planck equation and some similar equations. ...

In this paper we develop a technique for avoiding the order reduction caused by nonconstant boundary conditions in the methods called splitting, alternating direction or, more generally, fractional step methods. Such methods can be viewed as the combination of a semidiscrete in time procedure with a special type of additive Runge–Kutta method, which is called the fractional step Runge–Kutta met...

Freak waves are extreme ocean waves that are not predicted by traditional wave probability distributions. We study wave energy focusing, as a possible mechanism for freak wave formation, in a three-dimensional (3D) Numerical Wave Tank (NWT) solving fully nonlinear potential ow equations. The NWT combines a higher-order 3D-BEM and a Mixed-Eulerian-Lagrangian time updating of the free surface, ba...