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On numerical dispersion by upwind differencing
Applied Numerical Mathematics, 1986It is shown that any upwind biased scheme for the linear one-dimensional convection equation for the Courant-Friedrichs-Lewy (CFL) number \(\sigma\) in the range [0,1] is free of dispersion if it is applied in one step with CFL number \(\sigma\) followed by a step with CFL number 1-\(\sigma\).
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Analytical Investigations on FDTD Numerical Dispersion
2020 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO), 2020The numerical dispersion is one of the main factors to affect the accuracy of the finite-difference time-domain (FDTD) method. It can be easy to be taken for granted that a smaller time step leads to smaller simulation errors. This paper reveals that smaller time steps do not always make more accurate results in FDTD simulations.
Yu Cheng +3 more
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Numerical stability and dispersion
2016The finite-difference time-domain (FDTD) algorithm samples the electric and magnetic fields at discrete points both in time and space. The choice of the period of sampling (Δt in time, Δx, Δy, and Δz in space) must comply with certain restrictions to guarantee the stability of the solution.
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Mass flow, numerical dispersion and diffusion
1993If water containing dissolved salts (e.g. fertilizer) infiltrates into the soil, a gradual increase in salt concentration will be observed at a certain depth. The curve of the change in salt concentration against time at a certain depth is called the breakthrough curve. The rounded shape of this curve can partly be explained by diffusion of the salt in
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Numerical Dispersion and Anisotropy
2002As we saw in a previous section, a plane wave solution ei(ωt−k,x) of the continuous wave equation provides the following dispersion relation: $${\omega ^2} = {c^2}{\left| k \right|^2}.$$ (7.1)
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The Numerical Simulation of Hydrodynamic Dispersion
Mathematics in Oil Production, 1987We consider the problem of numerical simulation of hydrodynamic dispersion in porous media, in cases where the medium includes regions where the fluid velocity is unusually slow. This situation can occur at the microscopic level due to sufficient randomness in the pore space, or macroscopically in the presence of broad permeability distributions.
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Numerical Dispersion and Stability of the Time Domain Propagator Numerical Algorithm
2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2018The numerical dispersion and stability conditions for the full wave time domain propagator solution of Maxwell's equations are presented. The Propagator Method is a numerical integral operator technique for moving the electromagnetic field through a numerical space at successive time increments.
Jongchul Shin, Robert D. Nevels
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Numerical Studies of Unsteady Dispersion in Estuaries
Journal of the Sanitary Engineering Division, 1968A one-dimensional mathematical model is developed which describes the longitudinal concentration distribution of a pollutant in an estuary. The importance of including the tidal velocity in the advective term of the mass balance equation is emphasized.
Donald R. F. Harleman +2 more
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Numerical investigation of the Friedrichs mdoel dispersion relation
Journal of Computational Physics, 1974Abstract The numerical procedure of Marchand and a zero searching routine are applied to the study of the zero trajectories of the complex transcendental equation ω 0 − z − λ 2 ∫ 1 0 o(ω) ω − z dω − 2πiλ 2 o(z) = 0, where φ(ω) belongs to a class of fourth degree polynomials.
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Numerical prediction on the dispersion of pollutant particles
AIP Conference Proceedings, 2012The increasing concern on air pollution has led people around the world to find more efficient ways to control the problem. Air dispersion modeling is proven to be one of the alternatives that provide economical ways to control the growing threat of air pollution.
Osman, Kahar +3 more
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