In this paper, we consider the upwind difference scheme for singular perturbation problem (1.1). On a special discretization mesh, it is proved that the solution of the upwind difference scheme is first order converge...In this paper, we consider the upwind difference scheme for singular perturbation problem (1.1). On a special discretization mesh, it is proved that the solution of the upwind difference scheme is first order convergent, uniformly in the small parameter e , to the solution of problem (1.1). Numerical results are finally provided.展开更多
In this article,we discuss a new smart alternating group explicit method based on off-step discretization for the solution of time dependent viscous Burgers’equation in rectangu-lar coordinates.The convergence analys...In this article,we discuss a new smart alternating group explicit method based on off-step discretization for the solution of time dependent viscous Burgers’equation in rectangu-lar coordinates.The convergence analysis for the new iteration method is discussed in details.We compared the results of Burgers’equation obtained by using the proposed iterative method with the results obtained by other iterative methods to demonstrate computationally the efficiency of the proposed method.展开更多
The commercial and public services sectors including shopping centers,worship buildings,theatres,and other types,account for more than 20%of the electricity consumption in the world.These building typologies are chara...The commercial and public services sectors including shopping centers,worship buildings,theatres,and other types,account for more than 20%of the electricity consumption in the world.These building typologies are characterized by large spaces and high and temporary occupation.Besides,the horizontal temperature distribution in these buildings becomes one of the important parameters on occupant's comfort and energy efficiency.In the present study,a thermo-aeraulic zonal model using TRNSYS and CONTAM simulation tools is developed to analyze the spatial temperature distribution in a large building.Parametric studies relating to mesh discretization of building volume are performed to optimize the computational time and convergence.Extensive computational simulation is carried out to analyze the impact of building height,internal loads,natural ventilation and climatic conditions on the spatial temperature distribution,building energy performance,and thermal comfort.The developed simulation model in this study is effective to predict the horizontal temperature distribution with reasonable computation time compared to CFD simulations.The results show that the internal heat gains lead to an increase in the horizontal temperature gradient which should not be negligible especially in the case of large buildings.On the other side,natural night ventilation can reduce the peak tempearture in building by 3℃ for normal occupation building with limited internal gains.Furthermore,good spatial temperature distribution can decrease annual building energy needs about 32%.It can be helpful for architects and building developers to make an optimal choice regarding to building envelope and HVAC design.展开更多
Free-moving simulations of airplanes, submarines and other automobiles under extreme and emergency conditions are becoming increasingly important from operational and tactical perspectives. Such simulations are fairly...Free-moving simulations of airplanes, submarines and other automobiles under extreme and emergency conditions are becoming increasingly important from operational and tactical perspectives. Such simulations are fairly challenging due to the extreme unsteady motions and high Re(Reynolds) numbers. The aim of this study is to perform a six-DOF motion simulation of a 6:1prolate spheroid that is falling in a fluid field. Prior to conducting the six-DOF simulation, some verification simulations were performed. First, a laminar flow past an inclined prolate spheroid at a Re number of 1000 and incidence angle of 45. with a tetrahedral mesh was simulated to verify the relevant targeted discrete method for an unstructured mesh. Second, to verify the LES(large eddy simulation) models and dependent parameters for the DDES(delayed detached eddy simulation), a turbulent flow past a sphere was performed at a subcritical Re number of 10000. Third, a steady maneuvering problem about a prolate spheroid pitching up from 0. to 30. incidence at a uniform angular velocity was established based on a dynamic tetrahedral mesh with changing topology and the ALE(arbitrary Lagrangian-Eulerian) method of fluid-structure coupling at a Re number of 4.2 × 10~6.Finally, two six-DOF motions of an inclined 6:1 prolate spheroid at an initial incidence of 45. were simulated at different Re numbers of 10000 and 4.2 × 10~6.展开更多
文摘In this paper, we consider the upwind difference scheme for singular perturbation problem (1.1). On a special discretization mesh, it is proved that the solution of the upwind difference scheme is first order convergent, uniformly in the small parameter e , to the solution of problem (1.1). Numerical results are finally provided.
基金supported by"The Council of Scientific and Industrial Research"under research Grant No.09/045(0836)2009-EMR-I.
文摘In this article,we discuss a new smart alternating group explicit method based on off-step discretization for the solution of time dependent viscous Burgers’equation in rectangu-lar coordinates.The convergence analysis for the new iteration method is discussed in details.We compared the results of Burgers’equation obtained by using the proposed iterative method with the results obtained by other iterative methods to demonstrate computationally the efficiency of the proposed method.
文摘The commercial and public services sectors including shopping centers,worship buildings,theatres,and other types,account for more than 20%of the electricity consumption in the world.These building typologies are characterized by large spaces and high and temporary occupation.Besides,the horizontal temperature distribution in these buildings becomes one of the important parameters on occupant's comfort and energy efficiency.In the present study,a thermo-aeraulic zonal model using TRNSYS and CONTAM simulation tools is developed to analyze the spatial temperature distribution in a large building.Parametric studies relating to mesh discretization of building volume are performed to optimize the computational time and convergence.Extensive computational simulation is carried out to analyze the impact of building height,internal loads,natural ventilation and climatic conditions on the spatial temperature distribution,building energy performance,and thermal comfort.The developed simulation model in this study is effective to predict the horizontal temperature distribution with reasonable computation time compared to CFD simulations.The results show that the internal heat gains lead to an increase in the horizontal temperature gradient which should not be negligible especially in the case of large buildings.On the other side,natural night ventilation can reduce the peak tempearture in building by 3℃ for normal occupation building with limited internal gains.Furthermore,good spatial temperature distribution can decrease annual building energy needs about 32%.It can be helpful for architects and building developers to make an optimal choice regarding to building envelope and HVAC design.
基金supported by the National Natural Science Founation of China(Grant No.11572350)
文摘Free-moving simulations of airplanes, submarines and other automobiles under extreme and emergency conditions are becoming increasingly important from operational and tactical perspectives. Such simulations are fairly challenging due to the extreme unsteady motions and high Re(Reynolds) numbers. The aim of this study is to perform a six-DOF motion simulation of a 6:1prolate spheroid that is falling in a fluid field. Prior to conducting the six-DOF simulation, some verification simulations were performed. First, a laminar flow past an inclined prolate spheroid at a Re number of 1000 and incidence angle of 45. with a tetrahedral mesh was simulated to verify the relevant targeted discrete method for an unstructured mesh. Second, to verify the LES(large eddy simulation) models and dependent parameters for the DDES(delayed detached eddy simulation), a turbulent flow past a sphere was performed at a subcritical Re number of 10000. Third, a steady maneuvering problem about a prolate spheroid pitching up from 0. to 30. incidence at a uniform angular velocity was established based on a dynamic tetrahedral mesh with changing topology and the ALE(arbitrary Lagrangian-Eulerian) method of fluid-structure coupling at a Re number of 4.2 × 10~6.Finally, two six-DOF motions of an inclined 6:1 prolate spheroid at an initial incidence of 45. were simulated at different Re numbers of 10000 and 4.2 × 10~6.
