نتایج جستجو برای: advection diffusion equation

تعداد نتایج: 383602  

In the present study, analytical solutions are obtained for two-dimensional advection dispersion equation for conservative solute transport in a semi-infinite heterogeneous porous medium with pulse type input point source of uniform nature. The change in dispersion parameter due to heterogeneity is considered as linear multiple of spatially dependent function and seepage velocity whereas seepag...

Journal: :J. Comput. Physics 2009
Ercília Sousa

Abstract: The use of the conventional advection diffusion equation in many physical situations has been questioned by many investigators in recent years and alternative diffusion models have been proposed. Fractional space derivatives are used to model anomalous diffusion or dispersion, where a particle plume spreads at a rate inconsistent with the classical Brownian motion model. When a fracti...

Journal: :iranian journal of science and technology (sciences) 2013
a. r. soheili

in this paper, we propose a new method for solving the stochastic advection-diffusion equation of ito type. in this work, we use a compact finite difference approximation for discretizing spatial derivatives of the mentioned equation and semi-implicit milstein scheme for the resulting linear stochastic system of differential equation. the main purpose of this paper is the stability investigatio...

Journal: :J. Comput. Physics 2010
Hiroaki Nishikawa

In this paper, we unify advection and diffusion into a single hyperbolic system by extending the firstorder system approach introduced for the diffusion equation in [J. Comput. Phys., 227 (2007) 315-352] to the advection-diffusion equation. Specifically, we construct a unified hyperbolic advection-diffusion system by expressing the diffusion term as a first-order hyperbolic system and simply ad...

2007
D. Buske M. T. Vilhena T. Tirabassi

Atmospheric air pollution turbulent fluxes can be assumed to be proportional to themean concentration gradient. This assumption, alongwith the equation of continuity, leads to the advection-diffusion equation. Moreover, large eddies are able to mix scalar quantities in a manner that is counter to the local gradient. We present a general solution of a two-dimension steady state advection-diffusi...

Journal: :journal of agricultural science and technology 2013
m. mazaheri j. m. v. samani h. m. v. samani

advection-diffusion equation and its related analytical solutions have gained wide applications in different areas. compared with numerical solutions, the analytical solutions benefit from some advantages. as such, many analytical solutions have been presented for the advection-diffusion equation. the difference between these solutions is mainly in the type of boundary conditions, e.g. time pat...

2015
J. G. Zhou P. M. Haygarth P.J.A. Withers C.J.A. Macleod P. D. Falloon K. J. Beven M. C. Ockenden K. J. Forber M. J. Hollaway R. Evans A. L. Collins K. M. Hiscock C. Wearing R. Kahana M. L. Villamizar Velez

Mass transport such as movement of phosphorus in soils and solutes in rivers is a natural phenomenon and its study plays an important role in science and engineering. It is found that there are numerous practical diffusion phenomena that do not obey the classical advection-diffusion equation (ADE). Such diffusion is called abnormal or super diffusion and is well described using a fractional adv...

The parabolic partial differential equation arises in many application of technologies. In this paper, we propose an approximate method for solution of the heat and advection-diffusion equations using Laguerre-Gaussians radial basis functions (LG-RBFs). The results of numerical experiments are compared with the other radial basis functions and the results of other schemes to confirm the validit...

Journal: :J. Sci. Comput. 2011
J. H. M. ten Thije Boonkkamp Martijn Anthonissen

We present a new finite volume scheme for the advection-diffusion-reaction equation. The scheme is second order accurate in the grid size, both for dominant diffusion and dominant advection, and has only a three-point coupling in each spatial direction. Our scheme is based on a new integral representation for the flux of the one-dimensional advection-diffusion-reaction equation, which is derive...

Journal: :Physical review. E 2016
J G Zhou P M Haygarth P J A Withers C J A Macleod P D Falloon K J Beven M C Ockenden K J Forber M J Hollaway R Evans A L Collins K M Hiscock C Wearing R Kahana M L Villamizar Velez

Mass transport, such as movement of phosphorus in soils and solutes in rivers, is a natural phenomenon and its study plays an important role in science and engineering. It is found that there are numerous practical diffusion phenomena that do not obey the classical advection-diffusion equation (ADE). Such diffusion is called abnormal or superdiffusion, and it is well described using a fractiona...

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