Xinyi Guan¹, Shaoqiang Tang^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.1, pp. 1-1, 2024, DOI:10.32604/icces.2024.010869

Abstract Inheriting a convergence difficulty explained by the Kolmogorov N-width [1], the advection-diffusion equation is not effectively solved by the Proper Generalized Decomposition [2] (PGD) method. In this paper, we propose a new strategy: Proper Generalized Decomposition with Coordinate Transformation (CT-PGD). Converting the mixed hyperbolic-parabolic equation to a parabolic one, it resumes the efficiency of convergence for advection-dominant problems. Combining PGD with CT-PGD, we solve advection-diffusion equation by much fewer degrees of freedom, hence improve the efficiency. The advection-dominant regime and diffusion-dominant regime are quantitatively classified by a threshold, computed numerically. Moreover, we find that appropriate More >

Shumaila Azam¹, Nauman Ahmed^1,6, Ali Raza², Muhammad Sajid Iqbal¹, Muhammad Rafiq³, Ilyas Khan^4,*, Kottakkaran Sooppy Nisar⁵, Muhammad Ozair Ahmad¹, Zafar Iqbal^1,6

CMC-Computers, Materials & Continua, Vol.67, No.3, pp. 2933-2953, 2021, DOI:10.32604/cmc.2021.012396 - 01 March 2021

Abstract Recently, the world is facing the terror of the novel corona-virus, termed as COVID-19. Various health institutes and researchers are continuously striving to control this pandemic. In this article, the SEIAR (susceptible, exposed, infected, symptomatically infected, asymptomatically infected and recovered) infection model of COVID-19 with a constant rate of advection is studied for the disease propagation. A simple model of the disease is extended to an advection model by accommodating the advection process and some appropriate parameters in the system. The continuous model is transposed into a discrete numerical model by discretizing the domains, finitely.… More >

Naveed Shahid^1,2, Dumitru Baleanu^3,4,5, Nauman Ahmed^1,2, Tahira Sumbal Shaikh⁶, Ali Raza^7,*, Muhammad Sajid Iqbal¹, Muhammad Rafiq⁸, Muhammad Aziz-ur Rehman²

CMC-Computers, Materials & Continua, Vol.67, No.2, pp. 1713-1728, 2021, DOI:10.32604/cmc.2021.014191 - 05 February 2021

Abstract The novel coronavirus disease, coined as COVID-19, is a murderous and infectious disease initiated from Wuhan, China. This killer disease has taken a large number of lives around the world and its dynamics could not be controlled so far. In this article, the spatio-temporal compartmental epidemic model of the novel disease with advection and diffusion process is projected and analyzed. To counteract these types of diseases or restrict their spread, mankind depends upon mathematical modeling and medicine to reduce, alleviate, and anticipate the behavior of disease dynamics. The existence and uniqueness of the solution for… More >

Mahdi Saedshoar Heris¹, Mohammad Javidi¹, Bashir Ahmad^2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.121, No.1, pp. 249-272, 2019, DOI:10.32604/cmes.2019.08080

Abstract In this paper, we propose numerical methods for the Riesz space fractional advection-dispersion equations with delay (RFADED). We utilize the fractional backward differential formulas method of second order (FBDF2) and weighted shifted Grünwald difference (WSGD) operators to approximate the Riesz fractional derivative and present the finite difference method for the RFADED. Firstly, the FBDF2 and the shifted Grünwald methods are introduced. Secondly, based on the FBDF2 method and the WSGD operators, the finite difference method is applied to the problem. We also show that our numerical schemes are conditionally stable and convergent with the accuracy More >

Guofei Pang¹, Wen Chen^1,2, K.Y. Sze³

CMES-Computer Modeling in Engineering & Sciences, Vol.97, No.4, pp. 299-322, 2014, DOI:10.3970/cmes.2014.097.299

Abstract Space-fractional advection-diffusion equation is a promising tool to describe the solute anomalous transport in underground water, and it has been extended to multi-dimensions with the help of weighted, fractional directional diffusion operator [Benson, Wheatcraft and Meerschaert (2000)]. Due to the nonlocal property of the space-fractional derivative, it is always a challenge to develop an efficient numerical solution method. The present paper extends the polynomialbased differential quadrature and cubature methods to the solution of steady-state spatial fractional advection-diffusion equations on a rectangular domain. An improved differential cubature method is proposed which accelerates the solution process considerably. More >

Hui Wei^1,2,3, Wen Chen^1,2,4, HongGuang Sun^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.100, No.2, pp. 85-103, 2014, DOI:10.3970/cmes.2014.100.085

Abstract The unknown parameters are critical factors in fractional derivative advection-dispersion equation describing the solute transport in soil. For examples, the fractional derivative order is the index of anomalous dispersion, diffusion coefficient represents the dispersion ability of media and average pore-water velocity denotes the main trend of transport, etc. This paper is to develop a homotopy method to determine the unknown parameters of solute transport with spatial fractional derivative advection-dispersion equation in soil. The homotopy method can be easily developed to solve parameter determination problems of fractional derivative equations whose analytical solutions are difficult to obtain. More >

E. Tombarević¹, V. R. Voller², I. Vušanović¹

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.1, pp. 1-29, 2013, DOI:10.3970/cmes.2013.096.001

Abstract The Control Volume Finite Element Method (CVFEM) combines the geometric flexibility of the Finite Element Method (FEM) with the physical intuition of the Control Volume Method (CVM). These two features of the CVFEM make it a very powerful tool for solving heat and fluid flow problems within complex domain geometries. In solving problems in the two-dimensional domains the development of the CVFEM has been well documented. For the three-dimensional problems, while there is extensive reporting on the details of the numerical approximation, there is relatively sparse information on important issues related to data structure and More >

Chih-Wen Chang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.88, No.2, pp. 65-92, 2012, DOI:10.3970/cmes.2012.088.065

Abstract We utilize a regularized integral equation scheme to resolve the three-dimensional backward advection-dispersion equation (BADE) for identifying the groundwater pollution source identification problems in this research. First, the Fourier series expansion method is employed to estimate the concentration field C(x, y, z, t) at any time t < T. Second, we contemplate a direct regularization by adding an extra term a(x, y, z, 0) to transform a second-kind Fredholm integral equation for C(x, y, z, 0). The termwise separable property of the kernel function permits us to acquire a closed-form regularized solution. In addition, a More >

Gongsheng Li¹, De Yao², Hengyi Jiang³, Xianzheng Jia¹

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.2, pp. 83-108, 2011, DOI:10.3970/cmes.2011.074.083

Abstract This paper deals with an inverse problem of determining a time-depen -dent reaction coefficient arising from a disturbed soil-column infiltrating experiment based on measured breakthrough data. A purpose of doing such experiment is to simulate and study transport behaviors of contaminants when they vertically penetrating through the soils. Data compatibility of the inverse problem is discussed showing a sufficient condition to the solution's monotonicity and positivity with the help of an adjoint problem. Furthermore, an optimal perturbation regularization algorithm is applied to solve the inverse problem, and two typical numerical examples are presented to support More >

Ruben Avila¹, Zhidong Han², Satya N. Atluri³

CMES-Computer Modeling in Engineering & Sciences, Vol.71, No.4, pp. 363-396, 2011, DOI:10.3970/cmes.2011.071.363

Abstract The two dimensional steady state Stokes equations are solved by using a novel MLPG-Mixed Finite Volume method, that is based on the independent meshless interpolations of the deviatoric velocity strain tensor, the volumetric velocity strain tensor, the velocity vector and the pressure. The pressure field directly obtained from this method does not suffer from the malady of checker-board patterns. Numerical simulations of the flow field, and trajectories of passive fluid elements in a new complex Stokes flow are also presented. The new flow geometry consists of three coaxial cylinders two of smaller diameter, that steadily More >