Junsong Xiong¹, Zhen Wang², Shaofan Li³, Xin Lai^1,*, Lisheng Liu^2,*, Xiang Liu²

CMES-Computer Modeling in Engineering & Sciences, Vol.141, No.1, pp. 151-169, 2024, DOI:10.32604/cmes.2024.053078

Abstract Natural convection is a heat transfer mechanism driven by temperature or density differences, leading to fluid motion without external influence. It occurs in various natural and engineering phenomena, influencing heat transfer, climate, and fluid mixing in industrial processes. This work aims to use the Updated Lagrangian Particle Hydrodynamics (ULPH) theory to address natural convection problems. The Navier-Stokes equation is discretized using second-order nonlocal differential operators, allowing a direct solution of the Laplace operator for temperature in the energy equation. Various numerical simulations, including cases such as natural convection in square cavities and two concentric cylinders, More >

Marjan Uddin^1,*, Hameed Ullah Jan^1,*, Muhammad Usman²

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.2, pp. 797-819, 2020, DOI:10.32604/cmes.2020.08717

Abstract In this paper, we approximate the solution and also discuss the periodic behavior termed as eventual periodicity of solutions of (IBVPs) for some dispersive wave equations on a bounded domain corresponding to periodic forcing. The constructed numerical scheme is based on radial kernels and local in nature like finite difference method. The temporal variable is executed through RK4 scheme. Due to the local nature and sparse differentiation matrices our numerical scheme efficiently recovers the solution. The results achieved are validated and examined with other methods accessible in the literature. More >

Cheinshan Liu^1,2,3, Chunglun Kuo²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.4, pp. 189-191, 2019, DOI:10.32604/icces.2019.05074

Abstract For the linear differential operator equation equipped with boundary conditions we derive an energy identity. Then we propose an energy regularization technique to choose the energetic bases in the numerical solution of linear differential operator equation. In many meshless methods with some trial functions as the bases of numerical solution, there exist certain parameters in the numerical method. We derive a very simple energy gap functional and minimize it to determine the optimal parameters. The new methodology upon adopting optimal parameters by minimizing the energy gap functional can improve the accuracy of the meshless methods More >

Karol Miller

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.4, pp. 188-188, 2019, DOI:10.32604/icces.2019.06116

Abstract The field of Biomechanics is in the most exiting state of transition from the theoretical subject of the 20th century to a practical discipline providing patient-specific solutions in the 21st century. Computational biomechanics is becoming instrumental in enabling a new era of personalized medicine based on patient-specific scientific computations. The Finite Element Method is used by almost all members of computational biomechanics community to analyze mathematical models described by sets of partial differential equations. FEM, however, has a number of fairly serious theoretical and practical deficiencies when applied to highly deformable objects of very complicated… More >

S. Vahdati¹, D. Mirzaei²

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.3, pp. 247-262, 2015, DOI:10.3970/cmes.2015.109.247

Abstract 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 More >

Annamaria Mazzia¹, Giorgio Pini¹, Flavio Sartoretto²

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.4, pp. 239-262, 2015, DOI:10.3970/cmes.2015.108.239

Abstract Meshless Local Petrov Galerkin (MLPG) methods are pure meshless techniques for solving Partial Differential Equations (PDE). MLPG techniques are nowadays used for solving a huge number of complex, real–life problems. While MLPG aims to approximate the solution of a given differential problem, its “dual” Direct MLPG (DMLPG) technique relies upon approximating linear functionals. Assume adaptive methods are to be implemented. When using a mesh–based method, inserting and/or deleting a node implies complex adjustment of connections. Meshless methods are more apt to implement adaptivity, since they does not require such adjustments. Nevertheless, ad–hoc insertion and/or deletion… More >

Taku Itoh¹, Susumu Nakata²

CMES-Computer Modeling in Engineering & Sciences, Vol.107, No.3, pp. 187-199, 2015, DOI:10.3970/cmes.2015.107.187

Abstract To speed up generating a scalar field g(x) based on a piecewise polynomial, a new method for determining field values that are indispensable to generate g(x) has been proposed. In the proposed method, an intermediate for generating g(x) does not required, i.e., the field values can directly be determined from given point data. Numerical experiments show that the computation time for determining the field values by the proposed method is about 10.4–12.7 times less than that of the conventional method. In addition, on the given points, the accuracy of g(x) obtained by using the proposed More >

Chih-Ping Wu, Ruei-Yong Jiang

CMC-Computers, Materials & Continua, Vol.46, No.1, pp. 17-56, 2015, DOI:10.3970/cmc.2015.046.017

Abstract An asymptotic meshless method using the differential reproducing kernel (DRK) interpolation and multiple time scale methods is developed for the three-dimensional (3D) free vibration analysis of sandwich functionally graded material (FGM) circular hollow cylinders with combinations of simply-supported and clamped edge conditions. In the formulation, we perform the mathematical processes of nondimensionalization, asymptotic expansion and successive integration to obtain recurrent sets of motion equations for various order problems. Classical shell theory (CST) is derived as a first-order approximation of the 3D elasticity theory, and the motion equations for higher-order problems retain the same differential operators… More >

Chih-Ping Wu^1,2, Ruei-Yong Jiang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.97, No.3, pp. 239-279, 2014, DOI:10.3970/cmes.2014.097.239

Abstract A state space differential reproducing kernel (DRK) method is developed for the three-dimensional (3D) buckling analysis of simply-supported, carbon nanotube-reinforced composite (CNTRC) circular hollow cylinders and laminated composite ones under axial compression. The single-walled carbon nanotubes (CNTs) and polymer are used as the reinforcements and matrix, respectively, to constitute the CNTRC cylinder. Three different distributions of CNTs varying in the thickness direction are considered (i.e., the uniform distribution and functionally graded rhombus-, and X-type ones), and the through-thickness distributions of effective material properties of the cylinder are determined using the rule of mixtures. The 3D… More >

Annamaria Mazzia¹, Giorgio Pini¹, Flavio Sartoretto²

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.6, pp. 475-497, 2014, DOI:10.3970/cmes.2014.102.475

Abstract Meshless Local Petrov Galerkin (MLPG) methods are pure meshless techniques for solving Partial Differential Equations. One of pure meshless methods main applications is for implementing Adaptive Discretization Techniques. In this paper, we describe our fresh node–wise refinement technique, based upon estimations of the “local” Total Variation of the approximating function. We numerically analyze the accuracy and efficiency of our MLPG–based refinement. Solutions to test Poisson problems are approximated, which undergo large variations inside small portions of the domain. We show that 2D problems can be accurately solved. The gain in accuracy with respect to uniform More >