Journal of Computational Science and Technology 

About: Journal of Computational Science and Technology is an academic journal published by Japan Society Mechanical Engineers. The journal publishes majorly in the area(s): Finite element method & Computer science. It has an ISSN identifier of 1881-6894. Over the lifetime, 199 publications have been published receiving 930 citations.

Efficient and Robust Cartesian Mesh Generation for Building-Cube Method

Abstract: In this study, an efficient and robust Cartesian mesh generation method for Building-Cube Method (BCM) is proposed. It can handle “dirty” geometry data whose surface has cracks, overlaps, and reverse of triangle. BCM mesh generation is implemented by two procedures; cube generation and cell generation in each cube. The cell generation procedure in this study is managed in each cube individually, and parallelized by OpenMP. Efficiency of the parallelized BCM mesh generation is demonstrated for several three-dimensional test cases using a multi-core PC.

Explicit Evaluation of Hypersingular Boundary Integral Equation for 3-D Helmholtz Equation Discretized with Constant Triangular Element

Abstract: It is well known that the solution of an exterior acoustic problem governed by the Helmholtz equation is violated at the eigenfrequencies of the associated interior problem when the boundary element method (BEM) based on the conventional boundary integral equation (CBIE) is applied without any special treatment to solve it. To tackle this problem, the Burton-Miller formulation using a linear combination of the CBIE and its normal derivative (NDBIE) emerges as an effective and efficient formula which is proved to yield a unique solution for all frequencies if the imaginary part of the coupling constant of the two equations is nonzero. The most difficult part in implementing the Burton-Miller formulation is that the NDBIE is a hypersingular type, and it is often regularized by using the fundamental solution of the Laplace's equation. But various regularization procedures in the literature give rise to integrals which are still difficult and/or extremely time consuming to evaluate in general. However, when constant triangular elements are used to discretize the boundary, all the strongly-singular and hypersingular integrals can be evaluated in finite-part sense explicitly without any difficulty, and the numerical computation becomes more efficient than any other singularity-subtraction technique. Therefore, in this paper, these singular integrals are evaluated rigorously for triangular constant element as finite parts of the divergent integrals by canceling out the divergent terms which appears in the limiting process explicitly. The correctness of the formulation is also demonstrated through some numerical test examples.

An Inexact Balancing Preconditioner for Large-Scale Structural Analysis

Abstract: The balancing domain decomposition (BDD) method is a well-known preconditioner due to its excellent convergence rate The BDD method includes the Neumann-Neumann preconditioner and a coarse grid correction Several studies have considered applications of the BDD method to various phenomena and improvement of its convergence rate However, in applying the BDD method to large-scale problems, it is difficult to solve the coarse problem of a coarse grid correction since the size of the coarse problem increases in proportion to the number of subdomains (ie, the size of the original problem) Other preconditioners with a coarse grid correction have the same problem To overcome this problem, use of a new preconditioner, namely, incomplete balancing domain decomposition with a diagonal-scaling (IBDD-DIAG) method is proposed in this study The method is based on the BDD method, and constructed by an incomplete balancing preconditioner and a simplified diagonal-scaling preconditioner Moreover, it is parallelized by the hierarchical domain decomposition method To evaluate this new approach, some computational examples of large-scale problems are demonstrated

Analysis of Tire Tractive Performance on Deformable Terrain by Finite Element-Discrete Element Method

Abstract: The goal of this study is to develop a practical and fast simulation tool for soil-tire interaction analysis, where finite element method (FEM) and discrete element method (DEM) are coupled together, and which can be realized on a desktop PC. We have extended our formerly proposed dynamic FE-DE method (FE-DEM) to include practical soil-tire system interaction, where not only the vertical sinkage of a tire, but also the travel of a driven tire was considered. Numerical simulation by FE-DEM is stable, and the relationships between variables, such as load-sinkage and sinkage-travel distance, and the gross tractive effort and running resistance characteristics, are obtained. Moreover, the simulation result is accurate enough to predict the maximum drawbar pull for a given tire, once the appropriate parameter values are provided. Therefore, the developed FE-DEM program can be applied with sufficient accuracy to interaction problems in soil-tire systems.

Moving Computational Domain Method and Its Application to Flow Around a High-Speed Car Passing Through a Hairpin Curve

Abstract: This paper presents a new method for simulating flows driven by a body traveling with neither restriction on motion nor a limit of a region size. In the present method named 'Moving Computational Domain Method', the whole of the computational domain including bodies inside moves in the physical space without the limit of region size. Since the whole of the grid of the computational domain moves according to the movement of the body, a flow solver of the method has to be constructed on the moving grid system and it is important for the flow solver to satisfy physical and geometric conservation laws simultaneously on moving grid. For this issue, the Moving-Grid Finite-Volume Method is employed as the flow solver. The present Moving Computational Domain Method makes it possible to simulate flow driven by any kind of motion of the body in any size of the region with satisfying physical and geometric conservation laws simultaneously. In this paper, the method is applied to the flow around a high-speed car passing through a hairpin curve. The distinctive flow field driven by the car at the hairpin curve has been demonstrated in detail. The results show the promising feature of the method.