检索结果-南通市图书馆

Evaluating the different boundary conditions to simulate airflow and heat transfer in Double-Skin Facade

在线全文

学校读者我要写书评

暂无评论

Building Simulation 2022年第5期15卷 799-815页

作者： Javad Ahmadi Mohammadjavad Mahdavinejad Olena Kalyanova Larsen Chen Zhang Afsaneh Zarkesh Somayeh Asadi Highperformance Architecture Laboratory Department of ArchitectureTarbiat Modares UniversityJalal-e Al Ahmad HighwayNasr bridgeTehranIran Department of Built Environment Faculty of Engineering and ScienceDivision of Architectural EngineeringAalborg UniversityAalborgDenmark Department of Architectural Engineering Pennsylvania State UniversityPA 16801USA

The CFD simulation accuracy mostly depends on the appropriate setting of boundary conditions and numerical simulation parameters.This study shows the influence of two types of boundary condition settings on the CFD simulation results of Double-Skin Facade(DSF)for a specific problem.These two boundary settings are the constant temperature on the DSF surfaces called boundary A,and boundary B is defined via solar radiation using the Discrete Ordinate radiation Model(DOM).The paper verified both the numerical simulations using the experimental data.Comparing the numerical results of two types of boundaries with experimental data shows that both cases underestimated the values lower than 5.2 K and 0.1 m/s for the temperature and velocity respectively at the regarded measured points.boundary A gives more accurate temperature prediction results,while boundary B shows velocity magnitude closer to the measurements in the middle height of the cavity;the average temperature and velocity differences between the two boundary types are 0.6 K and 0.003 m/s respectively which are negligible.Finally,the selection of boundary conditions depends on study purposes,however,when the DSF is equipped with blinds and if there is not enough data in hand but the exact value of solar irradiation,using the boundary B approach is suggested;it can provide reasonable results associated with multi-type of thermal boundary conditions at the same time.Furthermore,if the goal is to investigate the flow pattern in the DSF,boundary B is argued to perform better than the constant temperature boundary condition.

关键词： Double-Skin Facade boundary conditions thermal performance airflow irradiation

Effects of heat transfer fluid and boundary conditions on temperature field of enhanced geothermal system

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum 2022年第3期8卷 436-445页

作者： Jie Zhang Meng Zhao Guiyang Wang School of Mechatronic Engineering Southwest Petroleum UniversityChengdu610500China

Enhanced geothermal system(EGS)is considered to be the most effective way to mine hot dry rock.A conceptual model of rock mass-fracture-rock mass was established to study the limitation of temperature,insulation and heat transfer on the temperature field of enhanced geothermal system and supercritical carbon dioxide enhanced geothermal system.The temperature field of the rock mass under three boundaries for 30 years has been obtained.Effects of fluid velocity,specific heat capacity and thermal conductivity of rock mass on the temperature field were studied.The results show that boundary conditions have a great influence on temperature change of the reservoir.Under three boundary conditions,flow velocity of the fluid has a great influence on the temperature.But thermal conductivity and specific heat capacity of the rock mass have a little influence on the temperature.Under the same boundary conditions,heat exchange effect of the supercritical carbon dioxide enhanced geothermal system is significantly better than that of the traditional enhanced geothermal system.

关键词： EGS boundary conditions Heat exchange fluid Supercritical carbon dioxide Temperature field

STABLE boundary conditions AND DISCRETIZATION FOR P_(N) EQUATIONS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2022年第6期40卷 977-1003页

作者： Jonas Bunger Neeraj Sarna Manuel Torrilhon Applied and Computational Mathematics(ACoM) Department of MathematicsRWTH Aachen UniversitySchinkelstr 252062 AachenGermany

A solution to the linear Boltzmann equation satisfies an energy bound,which reflects a natural fact:The energy of particles in a finite volume is bounded in time by the energy of particles initially occupying the volume augmented by the energy transported into the volume by particles entering the volume over time.In this paper,we present boundary conditions(BCs)for the spherical harmonic(P_(N))approximation,which ensure that this fundamental energy bound is satisfied by the P_(N) approximation.Our BCs are compatible with the characteristic waves of P_(N) equations and determine the incoming waves uniquely.Both,energy bound and compatibility,are shown on abstract formulations of P_(N) equations and BCs to isolate the necessary structures and properties.The BCs are derived from a Marshak type formulation of BC and base on a non-classical even/odd-classification of spherical harmonic functions and a stabilization step,which is similar to the truncation of the series expansion in the P_(N) method.We show that summation by parts(SBP)finite differences on staggered grids in space and the method of simultaneous approximation terms(SAT)allows to maintain the energy bound also on the semi-discrete level.

关键词： boundary conditions Energy stability Spherical harmonic(P_(N))approximation Kinetic theory Moment method Boltzmann Linear transport

boundary conditions for porous solids saturated with viscous fluid

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2009年第7期30卷 821-832页

作者： M.D.Sharma Department of Mathematics Kurukshetra University

boundary conditions are derived to represent the continuity requirements at the boundaries of a porous solid saturated with viscous fluid. They are derived from the physically grounded principles with a mathematical check on the conservation of energy. The poroelastic solid is a dissipative one for the presence of viscosity in the interstitial fluid. The dissipative stresses due to the viscosity of pore-fluid are well represented in the boundary conditions. The unequal particle motions of two constituents of porous aggre~ gate at a boundary between two solids are explained in terms of the drainage of pore-fluid leading to imperfect bonding. A mathematical model is derived for the partial connec- tion of surface pores at the porous-porous interface. At this interface, the loose-contact slipping and partial pore opening/connection may dissipate a part of strain energy. A numerical example shows that, at the interface between water and oil-saturated sandstone, the modified boundary conditions do affect the energies of the waves refracting into the isotropic porous medium.

关键词： porous solid dissipative boundary conditions

boundary conditions for Limited Area Models Based on the Shallow Water Equations

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2013年第8期14卷 664-702页

作者： Arthur Bousquet Madalina Petcu Ming-Cheng Shiue Roger Temam Joseph Tribbia The Institute for Scientific Computing and Applied Mathematics Indiana UniversityBloomingtonIN 47405USA Laboratoire de Mathematiques et Applications UMR 6086Universite de PoitiersFrance The Institute of Mathematics of the Romanian Academy BucharestRomania Department of Applied Mathematics National Chiao Tung UniversityHsinchuTaiwan National Center for Atmospheric Research BoulderColoradoUSA.

A new set of boundary conditions has been derived by rigorousmethods for the shallow water equations in a limited domain.The aim of this article is to present these boundary conditions and to report on numerical simulations which have been performed using these boundary conditions.The new boundary conditions which are mildly dissipative let the waves move freely inside and outside the domain.The problems considered include a one-dimensional shallow water system with two layers of fluids and a two-dimensional inviscid shallow water system in a rectangle.

关键词： boundary conditions finite volumes shallow water

boundary conditions of the dynamicnumerical model for the Chinese mainland lithosphere

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Seismologica Sinica(English Edition) 1999年第2期12卷 148-154页

作者：张东宁许忠淮 Institute of Geophysics China Seismological Bureau Beijing China

The numerical dynamic model of Chinese mainland lithosphere's stress and strain field was constructed withelasto-viscous creep constitive relation. The most recent data of the stress field of Chinese mainland and thehorizontal movement velocity of the crust blocks were used as constraint conditions. The values of the boundalsforce were computed by trial-and-error method. The effect of the Qinghai-Xizang Plateau's excess potential energyto the movement of Chinese mainland was studied also in this model. The results of the numerical computing showthat, recent rapid raising of the Qinghai-Xizang Plateau and the generation of normal faults in the southem part ofthe plateau resulted from the convergence of Indian Plate to the Eurasian Plate, and also from the rapid convectivethinning of the lower lithosphere. Horizontal extension of the Qinghai-Xizang Plateau is the main dynamic factorto torm the present tectonic framework of the Chinese mainland. The compressive loads on the eastern boundaryof the model were mainly applied by the subduction of the Pacific Plate. The compression from the PhilippinePlate maybe slight.

关键词： Chinese mainland stress field movement rate boundary conditions finite element

Interaction of edge dislocations with voids in tungsten

在线全文

学校读者我要写书评

暂无评论

Tungsten 2024年第3期6卷 633-646页

作者： Arseny Kazakov Rita I.Babicheva Aleksandr Zinovev Dmitry Terentyev Kun Zhou Elena A.Korznikova Sergey V.Dmitriev Research Laboratory for Metals and Alloys under Extreme Impacts Ufa University of Science and Technology Institute for Metals Superplasticity Problems of RAS School of Mechanical and Aerospace Engineering Nanyang Technological University Institute for Nuclear Energy Technology Belgian Nuclear Research Center Technological Machines and Equipment Department Ufa State Petroleum Technological University Institute of Mechanical Science Problems of RAS Institute of Molecule and Crystal Physics UFRC of Russian Academy of Sciences

Tungsten is widely used as a material capable of withstanding extreme operating conditions and is one of the candidates for use in fusion and Generation Ⅳ fission reactors.Atomistic modelling implemented to solve various material science problems is an indispensable approach for improving material properties.This work analyzes the interaction of an edge dislocation with a void in single-crystal tungsten with the help of molecular dynamics simulation.Two different approaches for studying the dynamics of dislocations in tungsten that differ in boundary conditions are compared.Multiple interactions of the dislocation and void at different temperatures are investigated,and based on the obtained stress-strain curves,the dislocation obstacle strength for voids having various diameters is defined.It is shown that when applied to a crystal with small voids,the model with the fixed boundary conditions returns incorrect results.Moreover,the influence of the cell size for the model with periodic boundary conditions is analyzed,and the case of a non-central interaction of a dislocation with a void is considered.The obtained results improve our understanding of the mechanical response of irradiated materials.

关键词： Tungsten Molecular dynamics method Dislocations Voids boundary conditions

Application of inverse method to estimation of boundary conditions during investment casting simulation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2009年第6期22卷 429-434页

作者： Haipeng JIN Jiarong LI Dong PAN National Key Laboratory of Advanced High Temperature Structural Materials Institute of AeronauticalMaterials Beijing 100095 China Key Lab for Advanced Materials Processing Technology MOE Department of Mechanical EngineeringTsinghua University Beijing 100084 China

Inverse method was used in single crystal superalloy DD6 processing simulation during solidification. Numerical modeling coupled with experiments has been used to estimate the interface heat transfer coefficient （IHTC） between the surface of slab casting and inner mold. Calculated temperature dependent values of IHTC were obtained from a numerical solution. The calculated temperatures agreed well with the measurement of cooling profile.

关键词： Numerical simulation Single crystal Inverse method boundary conditions

Frequency Analysis of Multiple Layered Cylindrical Shells under Lateral Pressure with Asymmetric boundary conditions

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2014年第1期27卷 23-31页

作者： ISVANDZIBAEI Mohammad Reza JAMALUDDIN Hishamuddin RAJA HAMZAH Raja Ishak Faculty of Mechanical Engineering Universiti Teknologi Malaysia

Natural frequency characteristics of a thin-walled multiple layered cylindrical shell under lateral pressure are studied. The multiple layered cylindrical shell configuration is formed by three layers of isotropic material where the inner and outer layers are stainless steel and the middle layer is aluminum. The multiple layered shell equations with lateral pressure are established based on Love＇s shell theory. The governing equations of motion with lateral pressure are employed by using energy functional and applying the Ritz method. The boundary conditions represented by end conditions of the multiple layered cylindrical shell are simply supported-clamped（SS-C）, free-clamped（F-C） and simply supported-free（SS-F）. The influence of different lateral pressures, different thickness to radius ratios, different length to radius ratios and effect of the asymmetric boundary conditions on natural frequency characteristics are studied. It is shown that the lateral pressure has effect on the natural frequency of multiple layered cylindrical shell and causes the natural frequency to increase. The natural frequency of the developed multilayered cylindrical shell is validated by comparing with those in the literature. The proposed research provides an effective approach for vibration analysis shell structures subjected to lateral pressure with an energy method.

关键词： multiple layered ritz method lateral pressure shell boundary conditions