We employ a two-dimensional spectral element method to investigate the effect of various semi-circular blockages on the laminar flow between two flat plates. This simplified geometry has a general relevance to blocked flows, but more academically, also relates to work on the backward-facing step, presenting a qualitatively similar flow with a single, independent step, or blockage, parameter. Th...

The thesis aims to solve partial differential equations numerically using mimetic spectral element method. The method rewrites the PDEs with differential forms so the resulting equations are able to preserve geometrical characteristics in physics. The equation we focus is the Poisson equation, which can be utilized for potential flow problems. The physical domain to be tested is a typical flow ...

We provide a detailed presentation and discussion of a numerical modeling technique for earthquake dynamics based on the spectral element method. The problem of dynamic frictional contact along slip interfaces in elastic domains is formulated in a hybrid variational form, with Lagrange multipliers associated to the fault tractions. The problem is discretized in space by a spectral element metho...

Magnesium is an abundant element in the environment. Magnesium ion sensing by fluorescence spectral method is of importance due to the need for the detection of the metal in the human body and the environment. In this paper, we report the Mg2+ ion sensing behavior of the phenylhydrazone derivative of a difluorenylpiperidin-4-one. The preparation method of this compound is simple. The compound s...

In this paper, the spectral element (SE) method is applied in time to find the entire time-periodic or transient solution of time-dependent differential equations. The time-periodic solution is computed by enforcing periodicity of the element set. Of particular interest are periodic forcing functions possessing high frequency content. To maintain the spectral accuracy for such forcing functions...

In this paper, flow past around two circular cylinders which are tandem arranged at a Reynolds number of 200 is numerically investigated by spectral element method. To validate the numerical method for incompressible Navier–Stokes equations, the benchmark problem of flow over a single circular cylinder is employed, with the numerical results in a good agreement with the available literatures. T...

The traveltimes of underside shear wave reflections (i.e. SS precursors) are widely used data for mapping the topography of mantle discontinuities in the upper mantle. Here, we examine the accuracy of ray theory in estimating the contribution of shear velocity heterogeneity in the mantle to SS–S400S, SS–S670S and S400S–S670S traveltimes. We analyse stacks of spectral-element method waveforms co...

This paper describes a novel numerical model aiming at solving moving-boundary problems such as free-surface flows or fluid-structure interaction. This model uses a moving-grid technique to solve the Navier–Stokes equations expressed in the arbitrary Lagrangian-Eulerian kinematics. The discretization in space is based on the spectral element method. The coupling of the fluid equations and the m...

Electrical and Computer Engineering) A Hybrid Spectral-Element / Finite-Element Time-Domain Method for Multiscale Electromagnetic Simulations by Jiefu Chen Department of Electrical and Computer Engineering Duke University

A high-order, conservative, yet efficient method named the spectral volume (SV) method is developed for conservation laws on unstructured grids. The concept of a “spectral volume” is introduced to achieve high-order accuracy in an efficient manner similar to spectral element and multidomain spectral methods. Each spectral volume is further subdivided into control volumes, and cell-averaged data...