Pub Date : 2004-03-01DOI: 10.1142/S1465876304002265
W. Yap, W. Asrar, M. K. Mawlood, A. Omar
Two higher-order compact finite difference approaches, the Hermitian and the Lax-Wendroff are examined by applying them to the viscous Burgers' equation. The difference equations obtained by the two methods were integrated in time through the third-order Strong-Stability-Preserving Runge-Kutta scheme. Absolute errors are computed by using an exact solution. The results are also compared with a second order central difference scheme. The Hermitian approach is far easier to implement. On uniform grids the Lax-Wendroff scheme produces smaller errors during the initial stages, but both methods are equally good for larger durations of integration. The convergence rate of the Hermitian scheme is slightly higher than the Lax-Wendroff scheme although both are of fourth order. Both schemes are unstable beyond a certain step size in time and space. When numerical boundary conditions are imposed, second-order conditions produce the best results whereas linear extrapolation proved to be the worst. It was also observed that large domains were required to implement the numerical boundary conditions properly. There was no detrimental effect on the accuracy of the results obtained through either of the two schemes when the size of the domain was greatly increased. Both schemes showed remarkable improvement in accuracy when clustered grids were employed. However much smaller time steps are required for stable solutions.
{"title":"A comparison of higher-order compact finite difference schemes through burgers' equation","authors":"W. Yap, W. Asrar, M. K. Mawlood, A. Omar","doi":"10.1142/S1465876304002265","DOIUrl":"https://doi.org/10.1142/S1465876304002265","url":null,"abstract":"Two higher-order compact finite difference approaches, the Hermitian and the Lax-Wendroff are examined by applying them to the viscous Burgers' equation. The difference equations obtained by the two methods were integrated in time through the third-order Strong-Stability-Preserving Runge-Kutta scheme. Absolute errors are computed by using an exact solution. The results are also compared with a second order central difference scheme. The Hermitian approach is far easier to implement. On uniform grids the Lax-Wendroff scheme produces smaller errors during the initial stages, but both methods are equally good for larger durations of integration. The convergence rate of the Hermitian scheme is slightly higher than the Lax-Wendroff scheme although both are of fourth order. Both schemes are unstable beyond a certain step size in time and space. When numerical boundary conditions are imposed, second-order conditions produce the best results whereas linear extrapolation proved to be the worst. It was also observed that large domains were required to implement the numerical boundary conditions properly. There was no detrimental effect on the accuracy of the results obtained through either of the two schemes when the size of the domain was greatly increased. Both schemes showed remarkable improvement in accuracy when clustered grids were employed. However much smaller time steps are required for stable solutions.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121885631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-03-01DOI: 10.1142/S1465876304002344
S. Küçükarslan, P. K. Banerjee
In this paper, inelastic pile-soil-structure interaction for dynamic analysis is formulated by coupling finite element and boundary element methods. Linear beam-column finite elements are used to model the piles and structural elements. The continuum is assumed to be elastic and an efficient step by step time integration scheme is implemented by using half space integral formulation. Inelastic modeling of soil media is done by a rational approximation to continuum with nonlinear interface springs along the piles. Modified Ozdemir's inelastic model is implemented and systems of equations are coupled for piles and pile groups. By using this mixed type of formulation, it is possible to get computationally most efficient and accurate results. In order to verify the proposed formulation, the result of a reported full-scale statnamic load tests are compared.
{"title":"Inelastic dynamic analysis of pile-soil-structure interaction","authors":"S. Küçükarslan, P. K. Banerjee","doi":"10.1142/S1465876304002344","DOIUrl":"https://doi.org/10.1142/S1465876304002344","url":null,"abstract":"In this paper, inelastic pile-soil-structure interaction for dynamic analysis is formulated by coupling finite element and boundary element methods. Linear beam-column finite elements are used to model the piles and structural elements. The continuum is assumed to be elastic and an efficient step by step time integration scheme is implemented by using half space integral formulation. Inelastic modeling of soil media is done by a rational approximation to continuum with nonlinear interface springs along the piles. Modified Ozdemir's inelastic model is implemented and systems of equations are coupled for piles and pile groups. By using this mixed type of formulation, it is possible to get computationally most efficient and accurate results. In order to verify the proposed formulation, the result of a reported full-scale statnamic load tests are compared.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130020551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-03-01DOI: 10.1142/S1465876304002332
M. Layeghi, A. Nouri-Borujerdi
The steady-state laminar and incompressible vapor flow in four partially-heated concentric annular heat pipe (CAHP) is studied. The governing equations are solved numerically, using finite volume approach based on collocated grids. The first order upwind scheme and the QUICK scheme are used in the numerical solution. The vapor pressure distributions and velocity profiles along the annular vapor space are predicted for a number of test cases in the range of low to moderate radial Reynolds numbers. The results show that in a partially-heated annular heat pipe, as the radial Reynolds number increases, a number of recirculation zones may be created at both ends of the evaporator and condenser sections. The size and location of the recirculation zones are predicted and their effects on the performance of an annular heat pipe are discussed qualitatively.
{"title":"Vapor flow analysis in partially-heated concentric annular heat pipes","authors":"M. Layeghi, A. Nouri-Borujerdi","doi":"10.1142/S1465876304002332","DOIUrl":"https://doi.org/10.1142/S1465876304002332","url":null,"abstract":"The steady-state laminar and incompressible vapor flow in four partially-heated concentric annular heat pipe (CAHP) is studied. The governing equations are solved numerically, using finite volume approach based on collocated grids. The first order upwind scheme and the QUICK scheme are used in the numerical solution. The vapor pressure distributions and velocity profiles along the annular vapor space are predicted for a number of test cases in the range of low to moderate radial Reynolds numbers. The results show that in a partially-heated annular heat pipe, as the radial Reynolds number increases, a number of recirculation zones may be created at both ends of the evaporator and condenser sections. The size and location of the recirculation zones are predicted and their effects on the performance of an annular heat pipe are discussed qualitatively.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131591719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-03-01DOI: 10.1142/S1465876304002319
Jie Wu, B. Jiang
A numerical method is presented to simulate dendritic crystal growth on a fixed mesh. The hyperbolic convective equation for the continuous phase field which identifies the solid and liquid phases is solved by the least-squares finite element method, and the heat conduction equation for the temperature field is solved by the Galerkin finite element method. Without special treatments this method can handle complicated interfacial shapes and physical features.
{"title":"Finite element simulation of dendritic crystal growth using a continuum approach","authors":"Jie Wu, B. Jiang","doi":"10.1142/S1465876304002319","DOIUrl":"https://doi.org/10.1142/S1465876304002319","url":null,"abstract":"A numerical method is presented to simulate dendritic crystal growth on a fixed mesh. The hyperbolic convective equation for the continuous phase field which identifies the solid and liquid phases is solved by the least-squares finite element method, and the heat conduction equation for the temperature field is solved by the Galerkin finite element method. Without special treatments this method can handle complicated interfacial shapes and physical features.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132289688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-03-01DOI: 10.1142/S146587630400223X
F. J. Wang, Y. Feng, D. Owen
A parallel computational strategy based on a distributed-memory environment is presented for simulating combined finite-discrete element systems comprising a large number of separate bodies. An explicit central difference scheme is used for the temporal integration of the governing equations. Some key issues, such as partitioning algorithms, load balance schemes and contact handling methods are discussed. A dual-level domain decomposition strategy is proposed to perform the dynamic domain decomposition. An implementation of this proposed strategy on cluster computing systems is described. MPI is adopted as the message passing library in this implementation. Numerical examples show that this implementation is suitable for simulating large scale problems. A dragline bucket filling model with 3 million degrees of freedom is built to demonstrate the parallel efficiency and scalability on a PC cluster.
{"title":"Parallelisation for finite-discrete element analysis in a distributed-memory environment","authors":"F. J. Wang, Y. Feng, D. Owen","doi":"10.1142/S146587630400223X","DOIUrl":"https://doi.org/10.1142/S146587630400223X","url":null,"abstract":"A parallel computational strategy based on a distributed-memory environment is presented for simulating combined finite-discrete element systems comprising a large number of separate bodies. An explicit central difference scheme is used for the temporal integration of the governing equations. Some key issues, such as partitioning algorithms, load balance schemes and contact handling methods are discussed. A dual-level domain decomposition strategy is proposed to perform the dynamic domain decomposition. An implementation of this proposed strategy on cluster computing systems is described. MPI is adopted as the message passing library in this implementation. Numerical examples show that this implementation is suitable for simulating large scale problems. A dragline bucket filling model with 3 million degrees of freedom is built to demonstrate the parallel efficiency and scalability on a PC cluster.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129641958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-03-01DOI: 10.1142/S1465876304002289
F. Rogier, A. Mancuso
This work aim to present a numerical method for solving ideal Magnetohydrodynamic equilibrium equations for Ultra Low Aspect Ratio Tokamak with pinch. Discretization and acceleration techniques are discussed and applications to realistic tokamak configurations are shown.
{"title":"A finite element integral method for calculating complex axisymetric plasma configurations","authors":"F. Rogier, A. Mancuso","doi":"10.1142/S1465876304002289","DOIUrl":"https://doi.org/10.1142/S1465876304002289","url":null,"abstract":"This work aim to present a numerical method for solving ideal Magnetohydrodynamic equilibrium equations for Ultra Low Aspect Ratio Tokamak with pinch. Discretization and acceleration techniques are discussed and applications to realistic tokamak configurations are shown.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125343899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-03-01DOI: 10.1142/S1465876304002277
P. Somasundaram, K. Kuppusamy, R. Devi
This paper presents an efficient, simple and new method for solving Economic Dispatch (ED) problem with line flow constraints through the application of Evolutionary Programming (EP). The controllable system quantities in the base-case state are optimized to minimize some defined objective function subject to the base-case operating constraints. A 10-bus system is taken for investigation. The ED results obtained using EP are compared with those obtained using quadratic programming. The investigations reveal that the proposed algorithm is relatively simple, reliable, efficient and suitable for on-line applications.
{"title":"Evolutionary programming based economic dispatch with line flow constraints","authors":"P. Somasundaram, K. Kuppusamy, R. Devi","doi":"10.1142/S1465876304002277","DOIUrl":"https://doi.org/10.1142/S1465876304002277","url":null,"abstract":"This paper presents an efficient, simple and new method for solving Economic Dispatch (ED) problem with line flow constraints through the application of Evolutionary Programming (EP). The controllable system quantities in the base-case state are optimized to minimize some defined objective function subject to the base-case operating constraints. A 10-bus system is taken for investigation. The ED results obtained using EP are compared with those obtained using quadratic programming. The investigations reveal that the proposed algorithm is relatively simple, reliable, efficient and suitable for on-line applications.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116666932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-03-01DOI: 10.1142/S1465876304002241
R. H. Shariffudin, Ithnin Abdul Jalil
It is very much desired to have subsystems resulting from finite difference modeling of partial differential equations where the matrices are block diagonal as the work required to solve such subsystems is reduced greatly. The simulation nodes in the red/black order and bound by the usual five-point finite difference molecule have their coefficient matrix with such pattern. In this paper, we attempt to have such subsystems for the coefficient matrix for the nodes bound by the nine-point molecule. This can be accomplished by the knight's move. A comparison of the performances between this model and the usual nine-point model is given. We note that the coefficient matrix favors the acceleration of the basic iterative methods.
{"title":"Simulations of the poisson type partial differential equations where the nodes are bound by the knight's moves","authors":"R. H. Shariffudin, Ithnin Abdul Jalil","doi":"10.1142/S1465876304002241","DOIUrl":"https://doi.org/10.1142/S1465876304002241","url":null,"abstract":"It is very much desired to have subsystems resulting from finite difference modeling of partial differential equations where the matrices are block diagonal as the work required to solve such subsystems is reduced greatly. The simulation nodes in the red/black order and bound by the usual five-point finite difference molecule have their coefficient matrix with such pattern. In this paper, we attempt to have such subsystems for the coefficient matrix for the nodes bound by the nine-point molecule. This can be accomplished by the knight's move. A comparison of the performances between this model and the usual nine-point model is given. We note that the coefficient matrix favors the acceleration of the basic iterative methods.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133544698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-03-01DOI: 10.1142/S1465876304002253
V. Kafka, M. Karlík
Mesomechanical constitutive modeling is applied to modeling cumulative damage and necking. The model is applied to the description of necking in specimens under uniaxial tension, and compared with experimental results received with specimens of pure iron and Fe-2.75wt%Si alloy. The process is modeled as a change in the structure; i.e. as a successive loss of continuity of the substructure of barriers resisting plastic deformation. It is shown that this model can be used for the evaluation of continuum damage, and of the description of: (i) the stress-strain diagrams up to rupture, (ii) the effect of the length of the specimen, (iii) the development of the form of the neck and its final form at rupture, (iv) the creation of internal residual energy.
{"title":"A mesomechanical constitutive modeling applied to cumulative damage and necking","authors":"V. Kafka, M. Karlík","doi":"10.1142/S1465876304002253","DOIUrl":"https://doi.org/10.1142/S1465876304002253","url":null,"abstract":"Mesomechanical constitutive modeling is applied to modeling cumulative damage and necking. The model is applied to the description of necking in specimens under uniaxial tension, and compared with experimental results received with specimens of pure iron and Fe-2.75wt%Si alloy. The process is modeled as a change in the structure; i.e. as a successive loss of continuity of the substructure of barriers resisting plastic deformation. It is shown that this model can be used for the evaluation of continuum damage, and of the description of: (i) the stress-strain diagrams up to rupture, (ii) the effect of the length of the specimen, (iii) the development of the form of the neck and its final form at rupture, (iv) the creation of internal residual energy.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117160994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-03-01DOI: 10.1142/S1465876304002320
C. Lucas, F. A. Azimi, J. Moghani, H. G. Fard
Switched reluctance motor (SRM) has been the subject of many investigations in recent years. The SR technology is a feasible and economically advantageous option for future electromotor production in Iran. However, computational intensive analysis methods (e.g. finite element (FE) analysis) and iterative search for optimal values of design parameters (e.g. genetic algorithms) cannot be jointly carried out online. In this paper, we outline a three-stages design process for determination of the optimal electromotor specifications. In the first stage, FE analysis is used for computation of performance characteristics associated with various design parameters. Next, an interpolator is trained to establish a mapping from design parameters to performance characteristics. Finally the latter values are optimized via multicriteria genetic algorithm.
{"title":"Design and multiobjective optimization of the parameters of switched reluctance motor","authors":"C. Lucas, F. A. Azimi, J. Moghani, H. G. Fard","doi":"10.1142/S1465876304002320","DOIUrl":"https://doi.org/10.1142/S1465876304002320","url":null,"abstract":"Switched reluctance motor (SRM) has been the subject of many investigations in recent years. The SR technology is a feasible and economically advantageous option for future electromotor production in Iran. However, computational intensive analysis methods (e.g. finite element (FE) analysis) and iterative search for optimal values of design parameters (e.g. genetic algorithms) cannot be jointly carried out online. In this paper, we outline a three-stages design process for determination of the optimal electromotor specifications. In the first stage, FE analysis is used for computation of performance characteristics associated with various design parameters. Next, an interpolator is trained to establish a mapping from design parameters to performance characteristics. Finally the latter values are optimized via multicriteria genetic algorithm.","PeriodicalId":331001,"journal":{"name":"Int. J. Comput. Eng. Sci.","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127183110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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