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Journal of Computational Physics (219991) 508
In this research article, we introduce a high-order and non-oscillatory finite volume method in combination with radial basis function approximations and use it for the solution of scalar conservation laws on unstructured meshes. This novel approach departs from conventional non-oscillatory techniques, which often require the use of multiple stencils to achieve smooth reconstructions. Instead, the new method uses a single central stencil and hinges on an approximate interpolation methodology called the weighted smoothed reconstruction (WSR), with a foundation on polyharmonic spline interpolation. Through some numerical experiments, we demonstrate the efficiency and accuracy of the new approach. It reduces the computational cost and performs well in capturing shocks and sharp solution fronts. © 2024 The Author(s)
Numerical Algorithms (10171398) 93(4)pp. 1759-1794
In this paper, we present a scattered data approximation method for detecting and approximating the discontinuities of a bivariate function and its gradient. The new algorithm is based on partition of unity, polyharmonic kernel interpolation, and principal component analysis. Localized polyharmonic interpolation in partition of unity setting is applied for detecting a set of fault points on or close to discontinuity curves. Then a combination of partition of unity and principal component regression is used to thinning the detected points by moving them approximately on the fault curves. Finally, an ordered subset of these narrowed points is extracted and a parametric spline interpolation is applied to reconstruct the fault curves. A selection of numerical examples with different behaviors and an application for solving scalar conservation law equations illustrate the performance of the algorithm. © 2023, The Author(s).
JOURNAL OF COMPUTATIONAL PHYSICS (00219991) 479
In this paper a new direct RBF partition of unity (D-RBF-PU) method is developed for numerical solution of partial differential equations defined on smooth orientable surfaces which are discretized with sets of scattered nodes and with approximations to normal vectors at each of the nodes. The accuracy, stability and efficiency of the new method are studied through some theoretical and experimental results. This method is a localized RBF based technique, results in a perfectly sparse final linear system, uses only scattered nodes on the surface rather than a connected mesh, and is applicable for a large class of PDEs on manifolds. Applications to some biological and chemical reaction-diffusion models are also given. Results show that the new method outperforms other comparable techniques for surface PDEs.(c) 2023 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons .org /licenses /by /4 .0/).
Computers and Mathematics with Applications (08981221) 127pp. 1-11
In this work we develop the standard Hermite interpolation based RBF-generated finite difference (RBF-HFD) method into a new faster and more accurate technique based on partition of unity (PU) method. In the new approach, much fewer number of local linear systems needs to be solved for calculating the stencil weights. This reduces the computational cost of the method, remarkably. In addition, the method is flexible in using different types of PU weight functions, smooth or discontinuous, each results in a different scheme with additional nice properties. We also investigate the scaling property of polyharmonic spline (PHS) kernels to develop a simple and stable algorithm for computing local approximants in PU patches. Experimental results confirm the efficiency and applicability of the proposed method. © 2022 Elsevier Ltd
Advances in Computational Mathematics (10197168) 47(5)
In this paper, we present a rational RBF interpolation method to approximate multivariate functions with poles or other singularities on or near the domain of approximation. The method is based on scattered point layouts and is flexible with respect to the geometry of the problem’s domain. Despite the existing rational RBF-based techniques, the new method allows the use of conditionally positive definite kernels as basis functions. In particular, we use polyharmonic kernels and prove that the rational polyharmonic interpolation is scalable. The scaling property results in a stable algorithm provided that the method be implemented in a localized form. To this aim, we combine the rational polyharmonic interpolation with the partition of unity method. Sufficient number of numerical examples in one, two and three dimensions are given to show the efficiency and the accuracy of the method. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Computers and Mathematics with Applications (8981221) 103pp. 1-11
We consider a least-squares variational kernel-based method for numerical solution of second order elliptic partial differential equations on a multi-dimensional domain. In this setting it is not assumed that the differential operator is self-adjoint or positive definite as it should be in the Rayleigh-Ritz setting. However, the new scheme leads to a symmetric and positive definite algebraic system of equations. Moreover, the resulting method does not rely on certain subspaces satisfying the boundary conditions. The trial space for discretization is provided via standard kernels that reproduce the Sobolev spaces as their native spaces. The error analysis of the method is given, but it is partly subjected to an inverse inequality on the boundary which is still an open problem. The condition number of the final linear system is approximated in terms of the smoothness of the kernel and the discretization quality. Finally, the results of some computational experiments support the theoretical error bounds. © 2021 Elsevier Ltd
SIAM Journal on Scientific Computing (10957197) 43(1)
In this paper, a new localized radial basis function (RBF) method based on partition of unity (PU) is proposed for solving boundary and initial-boundary value problems. The new method benefits from a direct discretization approach and is called the "direct RBF partition of unity (D-RBF-PU)"method. Thanks to avoiding all derivatives of PU weight functions as well as all lower derivatives of local approximants, the new method is faster and simpler than the standard RBF-PU method. Besides, the discontinuous PU weight functions can now be utilized to develop the method in a more efficient and less expensive way. Alternatively, the new method is an RBF-generated finite difference (RBF-FD) method in a PU setting which is much faster and in some situations more accurate than the original RBF-FD. The polyharmonic splines are used for local approximations, and the error and stability issues are considered. Some numerical experiments on irregular two- and three-dimensional domains, as well as cost comparison tests, are performed to support the theoretical analysis and to show the efficiency of the new method. © 2021 Society for Industrial and Applied Mathematics.
Numerical Methods for Partial Differential Equations (0749159X) 36(6)pp. 1682-1698
This paper concerns a numerical solution for the diffusion equation on the unit sphere. The given method is based on the spherical basis function approximation and the Petrov–Galerkin test discretization. The method is meshless because spherical triangulation is not required neither for approximation nor for numerical integration. This feature is achieved through the spherical basis function approximation and the use of local weak forms instead of a global variational formulation. The local Petrov–Galerkin formulation allows to compute the integrals on small independent spherical caps without any dependence on a connected background mesh. Experimental results show the accuracy and the efficiency of the new method. © 2020 Wiley Periodicals LLC
Computers and Mathematics with Applications (8981221) 79(9)pp. 2624-2643
In this paper, the idea of direct discretization via radial basis functions (RBFs) is applied on a local Petrov–Galerkin test space of a partial differential equation (PDE). This results to a weak-based RBF-generated finite difference (RBF–FD) scheme that possesses some useful properties. The error and stability issues are considered. When the PDE solution or the basis function has low smoothness, the new method gives more accurate results than the already well-established strong-based collocation methods. Although the method uses a Galerkin formulation, it still remains meshless because not only the approximation process relies on scattered point layouts but also integrations are done over non-connected, independent and well-shaped subdomains. Some applications to potential and elasticity problems on scattered data points support the theoretical analysis and show the efficiency of the proposed method. © 2019 Elsevier Ltd
Applied Numerical Mathematics (1689274) 150pp. 222-232
In this paper the error analysis of the kernel collocation method for partial differential equations on the unit sphere is presented. A simple analysis is given when the true solutions lie in arbitrary Sobolev spaces. This also extends the previous studies for true solutions outside the associated native spaces. Finally, some experimental results support the theoretical error bounds. © 2019 IMACS
Journal of Scientific Computing (8857474) 79(1)pp. 493-516
In this paper a numerical simulation based on radial basis functions is presented for the time-dependent Allen–Cahn equation on surfaces with no boundary. In order to approximate the temporal variable, a first-order time splitting technique is applied. The error analysis is given when the true solution lies on appropriate Sobolev spaces defined on surfaces. The method only requires a set of scattered points on a given surface and an approximation to the surface normal vectors at these points. Besides, the approach is based on Cartesian coordinates and thus any coordinate singularity has been omitted. Some numerical results are given to illustrate the ability of the technique on sphere, torus and red blood cell as three well-known surfaces. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
Acta Mechanica (15970) 229(6)pp. 2657-2673
This paper concerns a new and fast meshfree method for the linear coupled thermoelasticity problem. The resulting algorithm provides an attractive alternative to existing mesh-based and meshfree methods. Compared with mesh-based methods, the proposed technique inherits the advantages of meshfree methods allowing the use of scattered points instead of a predefined mesh. Compared with the existing meshfree methods, the proposed technique is truly meshless, requiring no background mesh for both trial and test spaces and, more importantly, numerical integrations are done over low-degree polynomials rather than complicated shape functions. In fact, this method mimics the known advantages of both meshless and finite element methods, where in the former triangulation is not required for approximation and in the latter the stiffness and mass matrices are set up by integration against simple polynomials. The numerical results of the present work concern the thermal and mechanical shocks in a finite domain considering classical coupled theory of thermoelasticity. © 2018, Springer-Verlag GmbH Austria, part of Springer Nature.
SIAM Journal on Numerical Analysis (361429) 56(1)pp. 274-295
In this paper, a numerical solution of partial differential equations on the unit sphere is given by using a kernel trial approximation in combination with a special Petrov–Galerkin test discretization. The solvability of the scheme is proved, and the error bounds are obtained for functions in appropriate Sobolev spaces. The condition number of the final system is estimated in terms of discretization parameters. The method is meshless because in the trial side the numerical solution parameterizes entirely in terms of scattered points and in the test side everything breaks down to simple numerical integrations over independent spherical caps. This means that no connected background mesh is required for either approximation or integration. © 2018 Society for Industrial and Applied Mathematics.
BIT Numerical Mathematics (63835) 57(4)pp. 1041-1063
In this paper a direct approximation method on the sphere, constructed by generalized moving least squares, is presented and analyzed. It is motivated by numerical solution of partial differential equations on spheres and other manifolds. The new method generalizes the finite difference methods, someway, for scattered data points on each local subdomain. As an application, the Laplace–Beltrami equation is solved and the theoretical and experimental results are given. The new approach eliminates some drawbacks of the previous methods. © 2017, Springer Science+Business Media Dordrecht.
Numerical Methods for Partial Differential Equations (0749159X) 32(3)pp. 847-861
The meshless local Petrov-Galerkin (MLPG) method with global radial basis functions (RBF) as trial approximation leads to a full final linear system and a large condition number. This makes MLPG less efficient when the number of data points is increased. We can overcome this drawback if we avoid using more points from the data site than absolutely necessary. In this article, we equip the MLPG method with the greedy sparse approximation technique of (Schaback, Numercail Algorithms 67 (2014), 531-547) and use it for numerical solution of partial differential equations. This scheme uses as few neighbor nodal values as possible and allows to control the consistency error by explicit calculation. Whatever the given RBF is, the final system is sparse and the algorithm is well-conditioned. © 2015 Wiley Periodicals, Inc.
Acta Mechanica (15970) 227(3)pp. 619-632
This article describes a new and fast meshfree method based on a generalized moving least squares (GMLS) approximation and the local weak forms for vibration analysis in solids. In contrast to the meshless local Petrov–Galerkin method, GMLS directly approximates the local weak forms from meshless nodal values, which shifts the local integrations over the low-degree polynomial basis functions rather than over the complicated MLS shape functions. Besides, if the method is set up properly, all local integrals have the same value if all local subdomains have the same shape. These features reduce the computational costs, remarkably. The new technique is called direct meshless local Petrov–Galerkin (DMLPG) method. In DMLPG, the stiff and mass matrices are constructed by integration against polynomials. This overcomes the main drawback of meshfree methods in comparison with the finite element methods (FEM). The Newmark scheme is adapted as a time integration method, and numerical results are presented for various dynamic problems. The results are compared with the exact solutions, if available, and the FEM solutions. © 2015, Springer-Verlag Wien.
Journal of Computational and Applied Mathematics (3770427) 294pp. 93-101
This paper provides the error estimates for generalized moving least squares (GMLS) derivatives approximations of a Sobolev function in Lp norms and extends them for local weak forms of DMLPG methods. Sometimes they are called diffuse or uncertain derivatives, but precisely they are direct approximants of exact derivatives which possess the optimal rates of convergence. GMLS derivatives approximations are different from the standard derivatives of MLS approximation. While they are much easier to evaluate at considerably lower cost, in this paper the same orders of convergence with comparison to the standard derivatives are obtained for them. © 2015 Elsevier B.V. All rights reserved.
Journal of Computational and Applied Mathematics (3770427) 282pp. 237-250
In this article the error estimation of the moving least squares approximation is provided for functions in fractional order Sobolev spaces. The analysis presented in this paper extends the previous estimations and explains some unnoticed mathematical details. An application to Galerkin method for partial differential equations is also supplied. © 2015 Elsevier B.V. All rights reserved.
Engineering Analysis with Boundary Elements (9557997) 59pp. 36-42
The aim of this work is application of the direct meshless local Petrov-Galerkin (DMLPG) method for solving a two-dimensional time fractional advection-diffusion equation. This method is based on the generalized moving least squares (GMLS) approximation, and makes a considerable reduction in the cost of numerical integrations in weak forms. In fact, DMLPG shifts the integrals over the close form polynomials rather than the complicated MLS shape functions. Moreover, the values of integrals on subdomains with the same shapes are equal. Thus DMLPG is a weak-based meshless technique in the cost-level of collocation or integration-free methods. In time domain, a simple and suitable finite difference approximation is employed. Some examples show the advantages of the new method in comparison with the traditional MLPG method. © 2015 Elsevier Ltd. All rights reserved.
CMES - Computer Modeling in Engineering and Sciences (15261492) 109(3)pp. 247-262
In this paper we present a meshless collocation method based on the moving least squares (MLS) approximation for numerical solution of the multiasset (d-dimensional) American option in financial mathematics. This problem is modeled by the Black-Scholes equation with moving boundary conditions. A penalty approach is applied to convert the original problem to one in a fixed domain. In finite parts, boundary conditions satisfy in associated (d-1)-dimensional Black-Scholes equations while in infinity they approach to zero. All equations are treated by the proposed meshless approximation method where the method of lines is employed for handling the time variable. Numerical examples for single- and two-asset options are illustrated. Copyright © 2015 Tech Science Press.
Applied Mathematical Modelling (0307904X) 39(23-24)pp. 7181-7196
In this paper, we continue the development of the Direct Meshless Local Petrov-Galerkin (DMLPG) method for elasto-static problems. This method is based on the generalized moving least squares approximation. The computational efficiency is the most significant advantage of the new method in comparison with the original MLPG. Although, the ''Petrov-Galerkin'' strategy is used to build the primary local weak forms, the role of trial space is ignored and direct approximations for local weak forms and boundary conditions are performed to construct the final stiffness matrix. In this modification the numerical integrations are performed over polynomials instead of complicated MLS shape functions. In this paper, DMLPG is applied for two and three dimensional problems in elasticity. Some variations of the new method are developed and their efficiencies are reported. Finally, we will conclude that DMLPG can replace the original MLPG in many situations. © 2015 Elsevier Inc. All rights reserved.
Numerical Algorithms (10171398) 65(2)pp. 275-291
As an improvement of the Meshless Local Petrov–Galerkin (MLPG), the Direct Meshless Local Petrov–Galerkin (DMLPG) method is applied here to the numerical solution of transient heat conduction problem. The new technique is based on direct recoveries of test functionals (local weak forms) from values at nodes without any detour via classical moving least squares (MLS) shape functions. This leads to an absolutely cheaper scheme where the numerical integrations will be done over low–degree polynomials rather than complicated MLS shape functions. This eliminates the main disadvantage of MLS based methods in comparison with finite element methods (FEM), namely the costs of numerical integration. © Springer Science+Business Media New York 2013.
Applied Numerical Mathematics (1689274) 68pp. 73-82
The Meshless Local Petrov–Galerkin (MLPG) method is one of the popular meshless methods that has been used very successfully to solve several types of boundary value problems since the late nineties. In this paper, using a generalized moving least squares (GMLS) approximation, a new direct MLPG technique, called DMLPG, is presented. Following the principle of meshless methods to express everything “entirely in terms of nodes” the generalized MLS recovers test functionals directly from values at nodes, without any detour via shape functions. This leads to a cheaper and even more accurate scheme. In particular, the complete absence of shape functions allows numerical integrations in the weak forms of the problem to be done over low-degree polynomials instead of complicated shape functions. Hence, the standard MLS shape function subroutines are not called at all. Numerical examples illustrate the superiority of the new technique over the classical MLPG. On the theoretical side, this paper discusses stability and convergence for the new discretizations that replace those of the standard MLPG. However, it does not treat stability, convergence, or error estimation for the MLPG as a whole. This should be taken from the literature on MLPG. © 2013 IMACS
Applied Mathematical Modelling (0307904X) 37(4)pp. 2337-2351
In this article the constant and the continuous linear boundary elements methods (BEMs) are given to obtain the numerical solution of the coupled equations in velocity and induced magnetic field for the steady magneto-hydrodynamic (MHD) flow through a pipe of rectangular and circular sections having arbitrary conducting walls. In recent decades, the MHD problem has been solved using some variations of BEM for some special boundary conditions at moderate Hartmann numbers up to 300. In this paper we develop this technique for a general boundary condition (arbitrary wall conductivity) at Hartmann numbers up to 105 by applying some new ideas. Numerical examples show the behavior of velocity and induced magnetic field across the sections. Results are also compared with the exact values and the results of some other numerical methods. © 2012 Elsevier Inc.
Engineering Analysis with Boundary Elements (9557997) 36(4)pp. 511-519
The meshless local boundary integral equation (MLBIE) method with an efficient technique to deal with the time variable are presented in this article to analyze the transient heat conduction in continuously nonhomogeneous functionally graded materials (FGMs). In space, the method is based on the local boundary integral equations and the moving least squares (MLS) approximation of the temperature and heat flux. In time, again the MLS approximates the equivalent Volterra integral equation derived from the heat conduction problem. It means that, the MLS is used for approximation in both time and space domains, and we avoid using the finite difference discretization or Laplace transform methods to overcome the time variable. Finally the method leads to a single generalized Sylvester equation rather than some (many) linear systems of equations. The method is computationally attractive, which is shown in couple of numerical examples for a finite strip and a hollow cylinder with an exponential spatial variation of material parameters. © 2011 Elsevier Ltd. ALl Rights Reserved.
IMA Journal of Numerical Analysis (2724979) 32(3)pp. 983-1000
The moving least squares (MLS) method provides an approximation û of a function u based solely on values u(xj) of u on scattered 'meshless' nodes xj. Derivatives of u are usually approximated by derivatives of û. In contrast to this, we directly estimate derivatives of u from the data, without any detour via derivatives of û. This is a generalized MLS technique, and we prove that it produces diffuse derivatives as introduced by Nyroles et al. (1992, Generalizing the finite element method: diffuse approximation and diffuse elements. Comput. Mech., 10, 307-318). Consequently, these turn out to be efficient direct estimates of the true derivatives, without anything 'diffuse' about them, and we prove optimal rates of convergence towards the true derivatives. Numerical examples confirm this, and we finally show how the use of shifted and scaled polynomials as basis functions in the generalized and standard MLS approximation stabilizes the algorithm. © 2010 The author. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.
CMES - Computer Modeling in Engineering and Sciences (15261492) 72(3)pp. 185-210
The meshless local Petrov-Galerkin (MLPG) method with an efficient technique to deal with the time variable are used to solve the heat conduction problem in this paper. The MLPG is a meshless method which is (mostly) based on the moving least squares (MLS) scheme to approximate the trial space. In this paper the MLS is used for approximation in both time and space domains, and we avoid using the time difference discretization or Laplace transform method to overcome the time variable. The technique is applied for continuously nonhomogeneous functionally graded materials (FGM) in a finite strip and a hallow cylinder. This idea can be easily extended to all MLS based methods such as the element free Galerkin (EFG), the local boundary integral equation (LBIE) and etc. © 2011 Tech Science Press.
Applied Numerical Mathematics (01689274) 60(3)pp. 245-262
This article describes a numerical scheme based on the moving least squares (MLS) method for solving integral equations in one- and two-dimensional spaces. For the MLS, nodal points spread over the analyzed domain, are utilized to approximate the unknown physical quantities. The method is a meshless method, since it does not require any background interpolation or approximation cells and it dose not depend to the geometry of domain. Thus for the two-dimensional Fredholm integral equation, a non-rectangular domain can be considered. Error analysis is provided for the new method. The proposed scheme is simple and computationally attractive. Applications are demonstrated through illustrative examples. © 2009 IMACS.
Journal of Computational and Applied Mathematics (03770427) 233(10)pp. 2737-2754
During the past few years, the idea of using meshless methods for numerical solution of partial differential equations (PDEs) has received much attention throughout the scientific community, and remarkable progress has been achieved on meshless methods. The meshless local Petrov-Galerkin (MLPG) method is one of the "truly meshless" methods since it does not require any background integration cells. The integrations are carried out locally over small sub-domains of regular shapes, such as circles or squares in two dimensions and spheres or cubes in three dimensions. In this paper the MLPG method for numerically solving the non-linear two-dimensional sine-Gordon (SG) equation is developed. A time-stepping method is employed to deal with the time derivative and a simple predictor-corrector scheme is performed to eliminate the non-linearity. A brief discussion is outlined for numerical integrations in the proposed algorithm. Some examples involving line and ring solitons are demonstrated and the conservation of energy in undamped SG equation is investigated. The final numerical results confirm the ability of proposed method to deal with the unsteady non-linear problems in large domains. © 2009 Elsevier B.V. All rights reserved.
Computational Mechanics (14320924) 46(6)pp. 805-812
Meshless local Petrov-Galerkin (MLPG) method is discussed for solving 2D, nonlinear, elliptic p-Laplace or p-harmonic equation in this article. The problem is transferred to corresponding local boundary integral equation (LBIE) using Divergence theorem. The analyzed domain is divided into small circular sub-domains to which the LBIE is applied. To approximate the unknown physical quantities, nodal points spread over the analyzed domain and MLS approximation, are utilized. The method is a meshless method, since it does not require any background interpolation and integration cells and it dose not depend on geometry of domain. The proposed scheme is simple and computationally attractive. Applications are demonstrated through illustrative examples. © 2010 Springer-Verlag.
Engineering Analysis with Boundary Elements (09557997) 33(4)pp. 522-528
This paper describes a numerical method based on the boundary integral equation and dual reciprocity methods for solving the one-dimensional Cahn-Hilliard (C-H) equation. The idea behind this approach comes from the dual reciprocity boundary element method that introduced for higher order dimensional problems. A time-stepping method and a predictor-corrector scheme are employed to deal with the time derivative and the nonlinearity respectively. Numerical results are presented for some examples to demonstrate the usefulness and accuracy of this approach. For these problems the energy functional dissipation and the mass conservation properties are investigated. © 2008 Elsevier Ltd. All rights reserved.
Engineering Analysis with Boundary Elements (09557997) 33(1)pp. 12-24
This article studies the boundary element solution of two-dimensional sine-Gordon (SG) equation using continuous linear elements approximation. Non-linear and in-homogenous terms are converted to the boundary by the dual reciprocity method and a predictor-corrector scheme is employed to eliminate the non-linearity. The procedure developed in this paper, is applied to various problems involving line and ring solitons where considered in references [Argyris J, Haase M, Heinrich JC. Finite element approximation to two-dimensional sine-Gordon solitons. Comput Methods Appl Mech Eng 1991;86:1-26; Bratsos AG. An explicit numerical scheme for the sine-Gordon equation in 2+1 dimensions. Appl Numer Anal Comput Math 2005;2(2):189-211, Bratsos AG. A modified predictor-corrector scheme for the two-dimensional sine-Gordon equation. Numer Algorithms 2006;43:295-308; Bratsos AG. The solution of the two-dimensional sine-Gordon equation using the method of lines. J Comput Appl Math 2007;206:251-77; Bratsos AG. A third order numerical scheme for the two-dimensional sine-Gordon equation. Math Comput Simul 2007;76:271-8; Christiansen PL, Lomdahl PS. Numerical solutions of 2+1 dimensional sine-Gordon solitons. Physica D: Nonlinear Phenom 1981;2(3):482-94; Djidjeli K, Price WG, Twizell EH. Numerical solutions of a damped sine-Gordon equation in two space variables. J Eng Math 1995;29:347-69; Dehghan M, Mirzaei D. The dual reciprocity boundary element method (DRBEM) for two-dimensional sine-Gordon equation. Comput Methods Appl Mech Eng 2008;197:476-86]. Using continuous linear elements approximation produces more accurate results than constant ones. By using this approach all cases associated to SG equation, which exist in literature, are investigated. © 2008 Elsevier Ltd. All rights reserved.
International Journal for Numerical Methods in Engineering (00295981) 79(13)pp. 1662-1682
In this paper the meshless local boundary integral equation (LBIE) method for numerically solving the non-linear two-dimensional sine-Gordon (SG) equation is developed. The method is based on the LBIE with moving least-squares (MLS) approximation. For the MLS, nodal points spread over the analyzed domain are utilized to approximate the interior and boundary variables. The approximation functions are constructed entirely using a set of scattered nodes, and no element or connectivity of the nodes is needed for either the interpolation or the integration purposes. A time-stepping method is employed to deal with the time derivative and a simple predictor-corrector scheme is performed to eliminate the non-linearity. A brief discussion is outlined for numerical integrations in the proposed algorithm. Some examples involving line and ring solitons are demonstrated and the conservation of energy in undamped SG equation is investigated. The final numerical results confirm the ability of method to deal with the unsteady non-linear problems in large domains. © 2009 John Wiley & Sons, Ltd.
Computer Physics Communications (00104655) 180(9)pp. 1458-1466
The meshless local boundary integral equation (LBIE) method is given to obtain the numerical solution of the coupled equations in velocity and magnetic field for unsteady magnetohydrodynamic (MHD) flow through a pipe of rectangular and circular sections with non-conducting walls. Computations have been carried out for different Hartmann numbers and at various time levels. The method is based on the local boundary integral equation with moving least squares (MLS) approximation. For the MLS, nodal points spread over the analyzed domain, are utilized to approximate the interior and boundary variables. A time stepping method is employed to deal with the time derivative. Finally, numerical results are presented to show the behaviour of velocity and induced magnetic field. © 2009 Elsevier B.V. All rights reserved.
Applied Numerical Mathematics (01689274) 59(5)pp. 1043-1058
In this article a meshless local Petrov-Galerkin (MLPG) method is given to obtain the numerical solution of the coupled equations in velocity and magnetic field for unsteady magnetohydrodynamic (MHD) flow through a pipe of rectangular section having arbitrary conducting walls. Computations have been carried out for different Hartmann numbers and wall conductivity at various time levels. The method is based on the local weak form and the moving least squares (MLS) approximation. For the MLS, nodal points spread over the analyzed domain are utilized to approximate the interior and boundary variables. A time stepping method is employed to deal with the time derivative. Finally numerical results are presented showing the behaviour of velocity and induced magnetic field across the section. © 2008 IMACS.
International Journal for Numerical Methods in Engineering (00295981) 76(4)pp. 501-520
A meshless local boundary integral equation (LBIE) method is proposed to solve the unsteady two- dimensional Schrödinger equation. The method is based on the LBIE with moving least-squares (MLS) approximation. For the MLS approximation, nodal points spread over the analyzed domain are utilized to approximate the interior and boundary variables. A time-stepping method is employed to deal with the time derivative. An efficient method for dealing with singular domain integrations that appear in the discretized equations is presented. Finally, numerical results are considered for some examples to demonstrate the accuracy, efficiency and high rate of convergence of this method. Copyright © 2008 John Wiley & Sons, Ltd.
Numerical Methods for Partial Differential Equations (10982426) 24(6)pp. 1405-1415
This article describes a numerical method based on the boundary integral equation and dual reciprocity method for solving the one-dimensional Sine-Gordon (SG) equation. The time derivative is approximated by the time-stepping method and a predictor-corrector scheme is employed to deal with the nonlinearity which appears in the problem. Numerical results are presented for some problems to demonstrate the use-fulness and. accuracy of this approach. In addition, the conservation of energy in SG equation is investigated. © 2008 Wiley Periodicals, Inc.
Computer Methods in Applied Mechanics and Engineering (00457825) 197(6-8)pp. 476-486
This paper presents the dual reciprocity boundary element method (DRBEM) for solving two-dimensional sine-Gordon (SG) equation. The integral equation formulation employs the fundamental solution of the Laplace equation, and hence a domain integral arises in the boundary integral equation. Furthermore, the time derivatives are approximated by the time-stepping method, and the domain integral also appears from these approximations. The domain integral is transformed into boundary integral by using the dual reciprocity method (DRM). The linear radial basis function (RBF) is employed for DRM. The dynamics of line solitons and ring solitons of circular and elliptic shapes are studied. Numerical results are presented for some problems involving line and ring solitons to demonstrate the usefulness and accuracy of this approach. © 2007.
Engineering Analysis with Boundary Elements (09557997) 32(9)pp. 747-756
In this paper the meshless local Petrov-Galerkin (MLPG) method is presented for the numerical solution of the two-dimensional non-linear Schrödinger equation. The method is based on the local weak form and the moving least squares (MLS) approximation. For the MLS, nodal points spread over the analyzed domain are utilized to approximate the interior and boundary variables. A time stepping method is employed for the time derivative. To deal with the non-linearity, we use a predictor-corrector method. A very simple and efficient method is presented for evaluation the local domain integrals. Finally numerical results are presented for some examples to demonstrate the accuracy, efficiency and high rate of convergence of this method. © 2007 Elsevier Ltd. All rights reserved.
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