Search results for "Numerical technique"
showing 6 items of 6 documents
An explicit unconditionally stable numerical solution of the advection problem in irrotational flow fields.
2004
A new methodology for the Eulerian numerical solution of the advection problem is proposed. The methodology is based on the conservation of both the zero- and the first-order spatial moments inside each element of the computational domain and leads to the solution of several small systems of ordinary differential equations. Since the systems are solved sequentially (one element after the other), the method can be classified as explicit. The proposed methodology has the following properties: (1) it guarantees local and global mass conservation, (2) it is unconditionally stable, and (3) it applies second-order approximation of the concentration and its fluxes inside each element. Limitation o…
Computational Homogenization of Heterogeneous Materials by a Novel Hybrid Numerical Scheme
2020
The Virtual Element Method (VEM) is a recent numerical technique capable of dealing with very general polygonal and polyhedral mesh elements, including irregular or non-convex ones. Because of this feature, the VEM ensures noticeable simplification in the data preparation stage of the analysis, especially for problems whose analysis domain features complex geometries, as in the case of computational micro-mechanics problems. The Boundary Element Method (BEM) is a well known, extensively used and effective numerical technique for the solution of several classes of problems in science and engineering. Due to its underlying formulation, the BEM allows reducing the dimensionality of the proble…
A Smoothed Particle Interpolation Scheme for Transient Electromagnetic Simulation
2006
In this paper, the fundamentals of a mesh-free particle numerical method for electromagnetic transient simulation are presented. The smoothed particle interpolation methodology is used by considering the particles as interpolation points in which the electromagnetic field components are computed. The particles can be arbitrarily placed in the problem domain: No regular grid, nor connectivity laws among the particles, have to be initially stated. Thus, the particles can be thickened only in distinct confined areas, where the electromagnetic field rapidly varies or in those regions in which objects of complex shape have to be simulated. Maxwell’s equations with the assigned boundary and initi…
Wick Theorem for General Initial States
2012
We present a compact and simplified proof of a generalized Wick theorem to calculate the Green's function of bosonic and fermionic systems in an arbitrary initial state. It is shown that the decomposition of the non-interacting $n$-particle Green's function is equivalent to solving a boundary problem for the Martin-Schwinger hierarchy; for non-correlated initial states a one-line proof of the standard Wick theorem is given. Our result leads to new self-energy diagrams and an elegant relation with those of the imaginary-time formalism is derived. The theorem is easy to use and can be combined with any ground-state numerical technique to calculate time-dependent properties.
A robust and efficient method for obtaining the complex modes in inhomogeneously filled waveguides
2003
In this paper, we present a computational simulation of the complex wave propagation in inhomogeneously filled waveguides with lossless and lossy dielectrics. We use a biorthonormal-basis method as a numerical technique. The behavior of complex modes in different waveguides whose characterization with other methods involves some difficulties is analyzed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 218–222, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10875
Analytical evaluation of structural response for stationary multicorrelated input
1990
Abstract An analytical procedure is presented which can drastically reduce computational effort in the evaluation of the spectral moments of an elastic linear multi-degree-of-freedom system subjected to a stationary multicorrelated input process. The reduction in computer time is possible since the cross-spectral moments of two oscillators can be obtained in recursive manner as a linear combination of the spectral moment of each oscillator taken separately, which is evaluated by means of a very fast numerical technique.