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疲劳试验中边界条件的模拟 被引量:1
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作者 李清蓉 《直升机技术》 2002年第1期29-32,共4页
本文主要以某型机上下夹板组件疲劳试验为例,阐述了疲劳试验中试验边界条件的模拟方法及其重要性。
关键词 夹板组件 疲劳试验 边界条件模拟 直升机
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偏心支撑框架空间子结构混合试验边界条件模拟方法 被引量:2
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作者 李腾飞 苏明周 +2 位作者 隋龑 弓欢学 马磊 《振动与冲击》 EI CSCD 北大核心 2022年第1期229-237,264,共10页
数值子结构的建模精度和子结构的边界条件模拟是子结构混合试验中的两个关键问题。为进一步研究这种新型结构试验方法对于空间框架结构的适用性,基于高强钢组合Y形偏心支撑框架模型展开研究。首先建立了一套由OpenSees,OpenFresco试验... 数值子结构的建模精度和子结构的边界条件模拟是子结构混合试验中的两个关键问题。为进一步研究这种新型结构试验方法对于空间框架结构的适用性,基于高强钢组合Y形偏心支撑框架模型展开研究。首先建立了一套由OpenSees,OpenFresco试验平台以及MTS加载系统组成的混合试验系统。然后分别针对2层、3层和4层3跨高强钢组合Y形偏心支撑框架,取底层带有偏心支撑的框架部分作为试验子结构,其余部分作为数值子结构在OpenSees中进行模拟。在混合试验之前,利用已有单榀试件拟静力试验结果对数值子结构的建模方法进行了数值模拟验证。最后选取El Centro波作为原始输入地震波,针对试验子结构的平动模拟和竖向荷载作用进行了一系列空间子结构混合试验。结果表明:通过数值模拟验证拟静力试验结果的方式,可以为混合试验中数值子结构的建模提供参考依据;采用双作动器水平加载来实现试验子结构的平动,可以有效考虑数值子结构对试验子结构的边界约束;竖向荷载的考虑,可以更真实的模拟试验子结构的重力二阶效应。 展开更多
关键词 边界条件模拟 混合试验 偏心支撑框架 空间子结构 OPENSEES
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以HCCI燃烧过程为主要研究对象的模拟燃烧系统 被引量:1
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作者 张纪鹏 常国峰 +2 位作者 董光宇 虞浏 夏元东 《汽车工程》 EI CSCD 北大核心 2006年第1期24-27,共4页
所论述的模拟燃烧系统是针对均质混合气压燃特性试验研究开发研制的装置,主要由燃烧系统主体部分、混合气配给系统等组成。该装置具备定压燃烧过程、复合燃烧过程以及定容燃烧过程的研究试验功能,且具有良好的边界条件可控性。燃烧系统... 所论述的模拟燃烧系统是针对均质混合气压燃特性试验研究开发研制的装置,主要由燃烧系统主体部分、混合气配给系统等组成。该装置具备定压燃烧过程、复合燃烧过程以及定容燃烧过程的研究试验功能,且具有良好的边界条件可控性。燃烧系统压缩终了压力可达到2.6MPa,活塞最高速度为5m/s,平均速度为2.18m/s。 展开更多
关键词 模拟燃烧系统.燃烧过程.边界条件
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飞行器温度响应边界条件模拟技术研究
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作者 杨志斌 《飞行器强度研究》 2020年第3期29-33,共5页
飞行器无论在进行热试验还是热结构数值仿真时都需要模拟真实的边界条件。本文介绍了热结构的几何条件、物理条件、初始条件和边界条件等四类定解条件,重点讨论了对流、辐射边界条件以及热阻边界条件,最后指出给定物体边界上的温度和给... 飞行器无论在进行热试验还是热结构数值仿真时都需要模拟真实的边界条件。本文介绍了热结构的几何条件、物理条件、初始条件和边界条件等四类定解条件,重点讨论了对流、辐射边界条件以及热阻边界条件,最后指出给定物体边界上的温度和给定物体边界上的热流的异同,为飞行器结构热设计提供理论指导。 展开更多
关键词 飞行器 热结构 边界条件模拟
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小卫星星座系统级EMC设计与验证 被引量:1
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作者 陶成华 李延东 《航天器工程》 CSCD 北大核心 2018年第6期34-40,共7页
针对小卫星星座系统级电磁兼容性(EMC)设计和验证的难度大、风险高等问题,从星座系统级EMC统筹设计和频率规划、星座系统EMC测试验证等方面,介绍小卫星星座系统级EMC设计及验证过程,提出基于最小资源占用的星座系统级EMC设计理念,以及... 针对小卫星星座系统级电磁兼容性(EMC)设计和验证的难度大、风险高等问题,从星座系统级EMC统筹设计和频率规划、星座系统EMC测试验证等方面,介绍小卫星星座系统级EMC设计及验证过程,提出基于最小资源占用的星座系统级EMC设计理念,以及基于模拟边界条件的逐级分步式EMC验证策略。小卫星星座应用实践结果表明:该设计理念可以显著降低星座频率资源、设备资源,减小EMC设计的频域隔离、空域隔离等难度;该验证策略可以尽早发现可能存在的EMC问题并及时解决,降低工程研制风险。设计理念和验证策略可行有效,可为复杂航天器系统的电磁兼容设计提供参考。 展开更多
关键词 小卫星星座 系统级电磁兼容性设计 最小资源占用 模拟边界条件
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环境振动试验技术的若干新进展 被引量:38
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作者 姜节胜 高跃飞 顾松年 《机械强度》 EI CAS CSCD 北大核心 2005年第3期307-311,共5页
阐述环境振动试验面临的新情况及其发生的背景。分析环境振动实验当前存在的问题,对柔性夹具、试件动力学边界条件的工程实现、振动台模态参数识别、结构的模态转换等新进展做简要介绍。对我国环境振动试验的近期发展进行简短的展望。
关键词 环境振动试验 柔性夹具 动力学边界条件模拟 模态参数识别 模态转换
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Application of the double absorbing boundary condition in seismic modeling 被引量:1
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作者 刘洋 李向阳 陈双全 《Applied Geophysics》 SCIE CSCD 2015年第1期111-119,123,共10页
We apply the newly proposed double absorbing boundary condition(DABC)(Hagstrom et al., 2014) to solve the boundary reflection problem in seismic finite-difference(FD) modeling. In the DABC scheme, the local high... We apply the newly proposed double absorbing boundary condition(DABC)(Hagstrom et al., 2014) to solve the boundary reflection problem in seismic finite-difference(FD) modeling. In the DABC scheme, the local high-order absorbing boundary condition is used on two parallel artificial boundaries, and thus double absorption is achieved. Using the general 2D acoustic wave propagation equations as an example, we use the DABC in seismic FD modeling, and discuss the derivation and implementation steps in detail. Compared with the perfectly matched layer(PML), the complexity decreases, and the stability and fl exibility improve. A homogeneous model and the SEG salt model are selected for numerical experiments. The results show that absorption using the DABC is considerably improved relative to the Clayton–Engquist boundary condition and nearly the same as that in the PML. 展开更多
关键词 Double absorbing boundary condition numerical modeling finite-difference method artificial boundary condition
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Numerical Simulation of the Flow around Two-dimensional Partially Cavitating Hydrofoils 被引量:2
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作者 Fahri Celik Yasemin Arikan Ozden Sakir Bal 《Journal of Marine Science and Application》 2014年第3期245-254,共10页
In the present study, a new approach is applied to the cavity prediction for two-dimensional (2D) hydrofoils by the potential based boundary element method (BEM). The boundary element method is treated with the so... In the present study, a new approach is applied to the cavity prediction for two-dimensional (2D) hydrofoils by the potential based boundary element method (BEM). The boundary element method is treated with the source and doublet distributions on the panel surface and cavity surface by usethe of the Dirichlet type boundary conditions. An iterative solution approach is used to determine the cavity shape on partially cavitating hydrofoils. In the case of a specified cavitation number and cavity length, the iterative solution method proceeds by addition or subtraction of a displacement thickness on the cavity surface of the hydrofoil. The appropriate cavity shape is obtained by the dynamic boundary condition of the cavity surface and the kinematic boundary condition of the whole foil surface including the cavity. For a given cavitation number the cavity length of the 2D hydrofoil is determined according to the minimum error criterion among different cavity lengths, which satisfies the dynamic boundary condition on the cavity surface. The NACA 16006, NACA 16012 and NACA 16015 hydrofoil sections are investigated for two angles of attack. The results are compared with other potential based boundary element codes, the PCPAN and a commercial CFD code (FLUENT). Consequently, it has been shown that the results obtained from the two dimensional approach are consistent with those obtained from the others. 展开更多
关键词 boundary element method (BEM):sheet cavitation CFD HYDROFOIL cavity closure model 2D hydrofoils
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Dynamic Response Analysis of Towed Cable During Deployment/Retrieval 被引量:3
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作者 王飞 黄国樑 邓德衡 《Journal of Shanghai Jiaotong university(Science)》 EI 2008年第2期245-251,共7页
A numerical approach was developed to analyze the transient behavior of towed cable during ac- tively controlled deployment/retrieval (DR).The cable motion is described by the lumped parameter method, its correspondin... A numerical approach was developed to analyze the transient behavior of towed cable during ac- tively controlled deployment/retrieval (DR).The cable motion is described by the lumped parameter method, its corresponding boundary conditions are presented.In view of its varying length during DR,two auxiliary arguments are introduced to describe its continuous varying length and discrete number of nodes(equations), the length is determined by the pay out(or reel-in) rate,which is then used to determine the node number by a logic relation.For the discrete mathematical model of towed cable,an algorithm was developed to deal with the discrete governing equations.The simulation results indicate that the cable experiences more com- plex motions due to its varying length,and tension fluctuates seriously in the startup and ending stage of deployment/retrieval.The effect of towing ship's motion in waves on cable during deployment/retrieval is also considered via numerical simulation. 展开更多
关键词 towed cable boundary conditions deployment/retrieval numerical simulation
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Effect of Viscosities on Mixing in A Patterned Micro Mixer
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作者 华硕 刘扬 许友生 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第5期952-956,共5页
The effect of viscosity and viscosity difference and boundary patterned slip on mixing in a micro mixer has been numerically studied using lattice Boltzmann method (LBM). The slip and no-slip ratio is not constant a... The effect of viscosity and viscosity difference and boundary patterned slip on mixing in a micro mixer has been numerically studied using lattice Boltzmann method (LBM). The slip and no-slip ratio is not constant and varies irregularly, and viscosity is altered by changing the relaxation time in LBE equation. The slip boundary condition is simulated by specular reflection boundary and the no-slip boundary condition is simulated by bounce back boundary. It has been found that it is feasible to optimize the micro mixer design by combining the viscosity effect and boundary patterned ratio altogether. 展开更多
关键词 micro mixing lattice Boltzmann method patterned boundary
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Multiple templates-based homology modeling and docking analysis of angiotensin Ⅱ type 1 receptor
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作者 谢云丰 蒋玉仁 +2 位作者 潘亚飞 陈丹 李传俊 《Journal of Central South University》 SCIE EI CAS 2012年第11期3033-3039,共7页
Using the latest reported homologous Chemokine receptors (PDB ID: 3ODU, 3OE0 and 3OE6) as templates, twenty models of angiotensin II (Ang II) type 1 (AT1) receptor (known as p30556) were generated by multiple... Using the latest reported homologous Chemokine receptors (PDB ID: 3ODU, 3OE0 and 3OE6) as templates, twenty models of angiotensin II (Ang II) type 1 (AT1) receptor (known as p30556) were generated by multiple templates homology modeling. According to the results of the initial validation of these twenty models, the model 0020 was finally chosen as the best one for further studies. Then, a 2 ns molecular dynamic (MD) simulation for model 0020 was conducted in normal saline (0.9%, w/F) under periodical boundary conditions, which was followed by docking studies of model 0020 with several existing AT1 receptor blockers (ARBs). The docking results reveal that model 0020 possesses good affinities with these docked ARBs which are in accordance with both the IC50 inhibitor values and their curative effects. The results also show more potent interactions between the model 0020 and its ARBs than those of ever reported results, such as hydrogen bonds, hydrophobic interactions, and especially cation-n interactions and π-π interactions which have never been reported before. This may reveal that the structure of the model 0020 is quite close to its real crystal structure and the model 0020 may have the potential to be used for structure based drug design: 展开更多
关键词 angiotensin II type 1 receptor DOCKING homology modeling molecular dynamics
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An element-free Galerkin method for ground penetrating radar numerical simulation 被引量:2
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作者 冯德山 郭荣文 王洪华 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第1期261-269,共9页
An element-free Galerkin method(EFGM) is used to solve the two-dimensional(2D) ground penetrating radar(GPR)modelling problems, due to its simple pre-processing, the absence of elements and high accuracy. Different fr... An element-free Galerkin method(EFGM) is used to solve the two-dimensional(2D) ground penetrating radar(GPR)modelling problems, due to its simple pre-processing, the absence of elements and high accuracy. Different from element-based numerical methods, this approach makes nodes free from the elemental restraint and avoids the explicit mesh discretization. First, we derived the boundary value problem for the 2D GPR simulation problems. Second, a penalty function approach and a boundary condition truncated method were used to enforce the essential and the absorbing boundary conditions, respectively. A three-layered GPR model was used to verify our element-free approach. The numerical solutions show that our solutions have an excellent agreement with solutions of a finite element method(FEM). Then, we used the EFGM to simulate one more complex model to show its capability and limitations. Simulation results show that one obvious advantage of EFGM is the absence of element mesh, which makes the method very flexible. Due to the use of MLS fitting, a key feature of EFM, is that both the dependent variable and its gradient are continuous and have high precision. 展开更多
关键词 element-free Galerkin method moving least-squares method ground penetrating radar forward simulation
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山东省被动式超低能耗居住建筑评价指标体系研究 被引量:9
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作者 王昭 宋文寅 +2 位作者 李震 李海滨 杨娇娇 《建筑科学》 CSCD 北大核心 2020年第10期119-124,共6页
本文结合《被动式超低能耗绿色建筑技术导则》(试行)(居住建筑)、德国被动房研究所(PHI)技术指标体系的有关计算公式,参考德国和欧盟等相关标准,选取山东省某省级被动式超低能耗居住建筑示范试点项目为工程案例,运用Design Builder能耗... 本文结合《被动式超低能耗绿色建筑技术导则》(试行)(居住建筑)、德国被动房研究所(PHI)技术指标体系的有关计算公式,参考德国和欧盟等相关标准,选取山东省某省级被动式超低能耗居住建筑示范试点项目为工程案例,运用Design Builder能耗模拟软件建立模型对其进行8760 h逐时计算,分析研究建筑年供热需求、年供冷需求、热负荷指标、冷负荷指标;并根据PHI和国家《导则》给出的计算公式进行稳态与非稳态、不同区域的比对分析和验证,最终确定山东省被动式超低能耗居住建筑的评价指标取值范围。 展开更多
关键词 被动式超低能耗建筑 逐时模拟计算 供热(冷)需求 模拟边界条件 评价指标
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新一代区域气候模式(CWRF)国内应用进展 被引量:14
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作者 刘冠州 梁信忠 《地球科学进展》 CAS CSCD 北大核心 2017年第7期781-787,共7页
随着区域气候模拟研究的不断深入,新一代区域气候模式CWRF因为其优异性能开始被广泛应用。从其对WRF物理过程的改良,模拟区域和侧边界条件的构建,个例模拟研究和与RegCM的模拟对比3个方面介绍CWRF模式在我国的发展与应用概况,说明CWRF... 随着区域气候模拟研究的不断深入,新一代区域气候模式CWRF因为其优异性能开始被广泛应用。从其对WRF物理过程的改良,模拟区域和侧边界条件的构建,个例模拟研究和与RegCM的模拟对比3个方面介绍CWRF模式在我国的发展与应用概况,说明CWRF在区域气候模拟中的准确性和先进性。探究了CWRF模式在国内的两大发展前景:一是在CWRF模式中引入更为准确的物理过程参数化方案,并可进行有机组合实现优化集成气候预报;二是把CWRF与全球气候模式嵌套,进行短期气候的业务预报和长期气候变化及其影响的预测评估。梳理和归纳CWRF模式在我国的应用现状,展望CWRF模式本土化的发展趋势,为CWRF模式的使用和研究提供有意义的参考。 展开更多
关键词 CWRF 模拟区域和侧边界条件 区域气候模式
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Numerical study of the flowing sequence of a pouring liquid 被引量:1
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作者 SUN ZhongGuo LIANG YangYang XI Guang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第8期1514-1519,共6页
Liquid flows in a particular sequence when it is poured out from an open-top receptacle. Since the sequence is hard to catch by experiment, a numerical simulation was performed in this pouring process with the moving ... Liquid flows in a particular sequence when it is poured out from an open-top receptacle. Since the sequence is hard to catch by experiment, a numerical simulation was performed in this pouring process with the moving particle semi-implicit (MPS) method. A modified solid-liquid boundary condition was verified and employed with a new definition of static liquid layers. The whole system was discretized by a set of particles and the liquid particles were marked and tracked in the pouring process. The flowing sequence of the liquid can be calculated by restoring the liquid particles back to their initial positions before it is poured. The mass transfer property is found to depend on the position of the rotation axis and the rotation speed, as well as the viscosity of the liquid. The mechanism of the flowing sequence results from a temporal vortex and its motion during the process. The character vortex is generated by the rotation of the container. The results reveal a principle for a versatile pouring process and may contribute to the applications in flowing control in many fields. 展开更多
关键词 meshless method particle method flowing sequence pouring liquid flow control
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A numerical study of a turbulent mixing layer and its generated noise 被引量:4
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作者 LI Dong GUO Li +1 位作者 ZHANG Xing HE GuoWei 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第6期1157-1164,共8页
A direct numerical simulation of a turbulent mixing layer with the Reynolds number 500 and the convective Mach number 0.6 is performed and the results obtained are used to study the turbulent flow field and its genera... A direct numerical simulation of a turbulent mixing layer with the Reynolds number 500 and the convective Mach number 0.6 is performed and the results obtained are used to study the turbulent flow field and its generated noise.In the present simulation,the numerical techniques of absorbing buffer zones,artificial convection velocity and spatial filtering are used to achieve nonreflecting boundary conditions.The self-similarity is used to validate the present numerical simulations.The large-scale coherent structures are plotted together with the acoustic waves,which demonstrates the directivity of acoustic waves.The Lighthill's source and space-time correlations are further investigated.The main contributions to mixing noise are identified in terms of large-scale coherent structures,Lighthill's source and space-time correlations. 展开更多
关键词 direct numerical simulation mixing layer space-time correlation noise
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Analysis of 2D Flow and Heat Transfer Modeling in Fracture of Porous Media 被引量:9
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作者 GUO Chunsheng NIAN Xianbo +3 位作者 LIU Yong QI Chao SONG Jinsheng YU Wenhe 《Journal of Thermal Science》 SCIE EI CAS CSCD 2017年第4期331-338,共8页
Heat and mass transfer between porous media and fluid is a complex coupling process, which is widely used in various fields of engineering applications, especially for natural and artificial fractures in oil and gas e... Heat and mass transfer between porous media and fluid is a complex coupling process, which is widely used in various fields of engineering applications, especially for natural and artificial fractures in oil and gas extraction. In this study, a new method is proposed to deal with the flow and heat transfer problem of steady flow in a fracture. The fluid flow in a fracture was described using the same method as Mohais, who considered a fracture as a channel with porous wall, and the perturbation method was used to solve the mathematical model. Unlike previous studies, the shear jump boundary condition proposed by Ochoa-Tapia and Whitaker was used at the interface between the fluid and porous media. The main methods were perturbation analysis and the application of shear jump boundary conditions. The influence of permeability, channel width, shear jump degree and effective dynamic viscosity on the flow and heat transfer in the channel was studied by analysing the analytical solution. The distribution of axial velocity in the channel with the change of the typical parameters and the sensitivity of the heat transfer was obtained. 展开更多
关键词 Heat and Mass Transfer FRACTURE Porous Media Stress Jump Boundary Condition Analytical Solution
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Simulation of Unsteady Flows with Fluctuating Inflow or Outflow Boundary Conditions
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作者 Jianjun Liu Guanghui ZhongInstitute of Engineering Thermophysics, Chinese Academy of Sciences, P.O. Box 2706, Beijing 100080, China 《Journal of Thermal Science》 SCIE EI CAS CSCD 2003年第2期162-166,共5页
This paper describes the numerical simulation of unsteady flows due to incoming wakes and/or varying back pressure,The solution method is based upon the one-step finite-volume TVD Lax-Wendroff scheme.Dual time-step ap... This paper describes the numerical simulation of unsteady flows due to incoming wakes and/or varying back pressure,The solution method is based upon the one-step finite-volume TVD Lax-Wendroff scheme.Dual time-step approach and multigrid algorithm are adopted to improve the computational efficiency of the baseline scheme.Numerical results for the transonic unsteady flow in a channel bump and the unsteady flow in a flat plate cascade and the VKI cascade are presented. 展开更多
关键词 numerical simulation unsteady flow fluctuating boundary conditions.
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A Variational Finite Element Model for Large-Eddy Simulations of Turbulent Flows 被引量:2
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作者 Toma's Chac'on REBOLLO Roger LEWANDOWSKI 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2013年第5期667-682,共16页
The authors introduce a new Large Eddy Simulation model in a channel, based on the projection on finite element spaces as filtering operation in its variationM form, for a given triangulation (Th)h〉0. The eddy visc... The authors introduce a new Large Eddy Simulation model in a channel, based on the projection on finite element spaces as filtering operation in its variationM form, for a given triangulation (Th)h〉0. The eddy viscosity is expressed in terms of the friction velocity in the boundary layer due to the wall, and is of a standard sub grid-model form outside the boundary layer. The mixing length scale is locally equal to the grid size. The computational domain is the channel without the linear sub-layer of the boundary layer. The no-slip boundary condition (or BC for short) is replaced by a Navier (BC) at the computational wall. Considering the steady state case, the authors show that the variational finite element model they have introduced, has a solution (Vh,Ph)h〉O that converges to a solution of the steady state Navier-Stokes equation with Navier BC. 展开更多
关键词 Navier-Stokes equations Turbulence modeling Finite elements
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A numerical study of the effect of the marginal sea on coastal upwelling in a non-linear inertial model
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作者 CHAO JiPing KANG YanYan LI JianPing 《Science China Earth Sciences》 SCIE EI CAS 2014年第11期2587-2596,共10页
Inertia theory and the finite element method are used to investigate the effect of marginal seas on coastal upwelling. In contrast to much previous research on wind-driven upwelling, this paper does not consider local... Inertia theory and the finite element method are used to investigate the effect of marginal seas on coastal upwelling. In contrast to much previous research on wind-driven upwelling, this paper does not consider localized wind effects, but focuses instead on temperature stratification, the slope of the continental shelf, and the background flow field. Finite element method, which is both faster and more robust than finite difference method in solving problems with complex boundary conditions, was developed to solve the partial differential equations that govern coastal upwelling. Our results demonstrate that the environment of the marginal sea plays an important role in coastal upwelling. First, the background flow at the outer boundary is the main driving force of upwelling. As the background flow strengthens, the overall velocity of cross-shelf flow increases and the horizontal scale of the upwelling front widens, and this is accompanied by the movement of the upwelling front further offshore. Second, temperature stratification determines the direction of cross-shelf flows, with strong stratification favoring a narrow and intense upwelling zone. Third, the slope of the continental shelf plays an important role in controlling the intensity of upwelling and the height that upwelling may reach: the steeper the slope, the lower height of the upwelling. An additional phenomenon that should be noted is upwelling separation, which occurs even without a local wind force in the nonlinear model. 展开更多
关键词 coastal upwelling inertia theory Finite Element Method (FEM)
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