检索结果-南通市图书馆

Imaging Rock Density Distribution beneath Liwa Fracture z.ne in the Southern Part of the Great Sumatran Fault System, Indonesia

引用

International Journal of Geosciences 2016年第4期7卷 598-614页

作者： Djedi S. Widarto Tedi Yudistira Jun-Ichi Nishida Ikuo Katsura eddy z. gaffar Susumu Nishimura Upstream Technology Center PT Pertamina (Persero) Jakarta Indonesia Department of Geophysical Engineering Bandung Institute of Technology Bandung Indonesia Faculty of Literary Ohtani University Kyoto Japan Kyoto Institute of Natural History Kyoto Japan Research Centre for Geotechnology—LIPI Bandung Indonesia

We have imaged rock density distribution beneath Liwa fracture z.ne in the southern part of the the Sumatran Fault z.ne by modelling and inverting Bouguer gravity data in two-and three-dimensional environments, respectively. The purpose of this study is aimed to figure out the subsurface distribution of rock densities associated with subsurface basement structure representing the evidence of trans-tensional tectonic product in the SF. In the gravity modeling, to eliminate distortions to the measured gravity values before modelling and inverting the data, Bouguer anomalies obtained in field measurements are reduced to the horiz.ntal plane of z.= +800 m as a representation of the average elevation in Liwa. For the inversion, we used algorithm implementing depth-and minimum volume weighting parameters in order to obtain a smooth model with better vertical resolution. The two-dimensional models show clearly surface topography of the basement rocks and the presence of normal faults. The reduced Bouguer anomaly of +800 m elevation shows the presence of structural lineaments extending primarily in a northwest-southeast direction, parallel to Sumatran Fault z.ne and older graben faults showing a negative flower structure. From the three-dimensional inversion, the model illustrates an increase of density contrast, lower values being found near the surface and higher values in the deeper parts. The lower density contrast of 0.15 to 0.3 g/cm3 found in the rock groups at depths of 2 km and less is characteristic of relatively homogeneous and poorly compacted rocks. Rocks with moderate to high density contrast (>1.0 g/cm3) are recogniz.d at depths of over 2 km. This model suggests a change of basement morphology as a function of depth, and delineates structural lineaments extending in northwest-southeast direction. This study supports the previous thought that Liwa area is underlain by graben structures, formed by trans-tensional tectonic events. Higher-den

关键词： Gravity Imaging Rock Density Fracture z.ne 2D Modeling 3D Inversion Density Contrast

来源：

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

Numerical Study of Flow Features Around Submerged Circular and Square Piles at Flat and Scoured Beds Using OpenFOAM

引用

Journal of Ocean University of China 2024年第4期23卷 897-914页

作者： WANG Chaolin WU Guoxiang WANG Dianhe DU Shengtao z.ANG z.iyong JIN Heng z.U David z. LIANG Bingchen Donghai Academy School of Civil&Environmental Engineering and Geography ScienceNingbo UniversityNingbo 315211China Key Laboratory of Estuary and Coast of z.ejiang Province and Zhejiang Institute of Hydraulics and EstuaryHangzhou 310020China Shandong Provincial Key Laboratory of Ocean Engineering and College of EngineeringOcean University of ChinaQingdao 266100China Shandong Water Conservancy Vocational College Rizhao 276826China School of Mechanical and Energy Engineering Ningbotech UniversityNingbo 315211China

Elucidating the flow features around piles in local scouring processes is crucial for studies of local scouring mechanisms and scour depth *** study details the flow turbulence characteristics of two submerged piles that are determined by solving the Navier-Stokes equations with the improved delayed detached eddy simulation *** model is verified by comparing experimental and numerical results for hydrodynamic parameters with the literature for both square-crossing piles(SCPs)and circular-crossing piles(CCPs).Original topographies of flat and scoured beds(i.e.,the initial and equilibrium scouring stages)are based on experimental results obtained by the authors in the present *** and CCP flow features in the scouring process are *** results indicate that during the scouring process,the time-averaged drag coefficient and root mean square(rms)of the lift coefficient increase linearly in the CCP test,while the rms of the lift coefficient in the SCP test decreases ***,the minimum pressure coefficient is always located in the upstream corners in the SCP case but moves from 72.5°to 79.5°when the scour hole is completely developed in the CCP *** flow behind the pile,which is generated by separated boundary layers above the top face of the pile,can reach the sand bed and turn the separated shear layers into patches of small vortices in the near-wake ***,the high shear stress z.nes are mainly at the scour edges under scoured-bed conditions.

关键词： flat bed scoured bed local scour OpenFOAM bed shear stress

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Prediction of Boundary Layer Transition Based on Modeling of Laminar Fluctuations Using RANS Approach

引用

Chinese Journal of Aeronautics 2009年第2期22卷 113-120页

作者： Rez. Taghavi z. Mahmood Salary Amir Kolaei Department of Mechanical Engineering Iran University of Science and Technology Tehran 16846 Iran

This article presents a linear eddy-viscosity turbulence model for predicting bypass and natural transition in boundary layers by using Reynolds-averaged Navier-Stokes (RANS) equations. The model includes three transport equations, separately, to compute laminar kinetic energy, turbulent kinetic energy, and dissipation rate in a flow field. It needs neither correlations of intermittency factors nor knowledge of the transition onset. Two transition tests are carried out: flat plate boundary layer under z.ro ...

关键词： boundary layer transition eddy-viscosity turbulence model laminar fluctuations

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Large eddy simulation of turbulent diffusion flame combustion using a conserved scalar methodology

引用

航空动力学报 2007年第7期22卷 1106-1117页

作者： K. Wang z. Yang J. J. McGuirk Department of Aeronautical and Automotive EngineeringLoughborough University Loughborough Leicestershire LE11 3TU UK

The present paper describes an LES prediction of turbulent diffusion flame combustion in a simplifled axi-symmetric combustor *** calculations are carried out using a well-tested finite volume incompressible LES code which has been modified to handle variable density and reacting *** basic mixture fraction conserved scalar method *** with the chemical state relationships described by fast *** turbulence-chemistry interaction is modelled by a sub-grid PDF method and the PDF is assumed to follow a Beta-function *** LES predictions have been time-averaged over 3.5 flow-through times to generate the mean radial profiles of mixture fraction,product mass fraction,temperature,axial velocity and axial *** agreement of the LES predictions with the experimental data is good for all the above quantities at four different axial positions with largest differences at the first measurement *** LES method also provides information on the unsteady nature of turbulent diffusion *** turbulent reacting flows with large density ratio,it was found necessary to use a relaxation method in order to remove unphysical high-frequency fluctuations and to maintain numerical stability.

关键词：大涡模拟湍流扩散数量方法论弛豫法燃烧理论

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ammonia borane-based reactive mixture for trapping and converting carbon dioxide

引用

Frontiers of Materials Science 2022年第2期16卷 71-81页

作者： Carlos A.CASTILLA-MARTINEz.Bilge COŞKUNER FİLİz.eddy PETIT Aysel KANTÜRK FİGEN Umit B.DEMIRCI Institut Europeen des Membranes(IEM) UMR 5635Univ MontpellierENSCMCNRSMontpellierFrance Department of Metallurgy and Materials Engineering Yildiz Technical UniversityİstanbulTurkey Department of Chemical Engineering Yildiz Technical UniversityİstanbulTurkey

Ammonia borane(NH_(3)BH_(3))is a reducing agent,able to trap and convert carbon *** the present work,we used a reactive solid consisting of a mixture of 90 wt.%of NH_(3)BH_(3)and 10 wt.%of palladium chloride,because the mixture reacts in a fast and exothermic way while releasing H2 and generating catalytic *** took advantage of such reactivity to trap and convert CO_(2)(7 bar),knowing besides that Pd0 is a CO_(2)hydrogenation *** operation(*** 1)was effective:BNH polymers,and B−O,C=O,C−O,and C−H bonds(like in BOCH_(3)and BOOCH groups)were *** then(in stage 2)pyrolyz.d the as-obtained solid at 1250℃ and washed it with *** doing so,we isolated cyclotriboric acid H_(3)B3O6(stemming from B2O3 formed at 1250℃),hexagonal boron nitride,and graphitic *** conclusion,the stage 1 showed that CO_(2)can be‘trapped’and converted,resulting in the formation of BOCH_(3)and BOOCH groups(possible sources of methanol and formic acid),and the stage 2 showed that CO_(2)transforms into graphitic carbon.

关键词： ammonia borane boron nitride boron oxide carbon dioxide graphitic carbon

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An Efficient Approach for the Numerical Identification of R and L Parameters of High Frequency Multi-winding Transformers

引用

Journal of Energy and Power Engineering 2011年第7期5卷 641-650页

作者： z. De Greve O. Deblecker J. Lobry Power Electrical Engineering Department Faculty of Engineering University of Mons Mons 7000 Belgium Belgian Fund for Researeh F.R.S/FNRS Brussels 1000 Belgium

In this paper, equivalent circuits for high frequency multi-winding magnetic components are derived from finite element （FE） computations. Lumped parameter models are first presented, based on previously published work. All parameters of these circuits can be interpreted as the results of open and short-circuit tests on the transformer. Based on this consideration, numerical procedures are then proposed to derive frequency-dependent lumped parameters from FE simulations. By using an adequate formulation, parameters are directly obtained from the FE model degrees of freedom, without performing any volume integration in post-processing, which can be source of numerical errors. In this contribution, attention is paid on the modeling of magnetic coupling using inductances, and dissipative effects （winding and core losses） using resistances. The impact of conductor eddy currents on the circuit parameters is moreover studied in details. Instead of an analysis of the impact conductor eddy currents may have on the circuit parameters is moreover carried through.

关键词： Multi-winding transformer finite elements lumped parameter circuits.

来源：

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

A Mathematical Analysis of Scale Similarity

引用

Communications in Computational Physics 2017年第1期21卷 149-161页

作者： z.J.Wang Yanan Li Department of Aerospace Engineering University of Kansas2120 Learned HallLawrenceKS 66045USA

Scale similarity is found in many natural phenomena in the universe,from fluid dynamics to *** large eddy simulations of turbulent flows,some sub-grid scale(SGS)models are based on scale *** earliest scale similarity SGS model was developed by Bardina et al.,which produced SGS stresses with good correlation to the true *** the present study,we perform a mathematical analysis of scale *** analysis has revealed that the ratio of the resolved stress to the SGS stress is g2,where g is the ratio of the second filter width to the first filter width,under the assumption of small filter *** implications of this analysis are discussed in the context of large eddy simulation.

关键词： Scale similarity large eddy simulation sub-grid scale models

来源：

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

Benchmark for scale-resolving simulation with curved walls: the Taylor Couette flow

引用

Advances in Aerodynamics 2021年第1期3卷 281-298页

作者： z.J.Wang E.Jourdan Department of Aerospace Engineering University of KansasLawrenceKS 66045USA

Flow between rotating concentric cylinders,or the Taylor Couette flow,has been studied extensively because of its rich physics,ranging from axisymmetric steady laminar flow,to fully developed turbulent *** the present study,we advocate the use of this problem as a benchmark case for scale-resolving simulation,such as large eddy simulation(LES)and direct numerical simulation(DNS).The problem is attractive because of its simple geometry,simple boundary conditions,and complex physics involving wall-shear induced and centrifugal *** the wellknown fully developed channel flow,this problem has a curved wall boundary,and it is unnecessary to add a source term to the governing equations to sustain the fully developed turbulent flow.A p-refinement study for Re=4000 is performed first to establish DNS data,including the time history of enstrophy,which can be used as an accuracy and resolution indicator to evaluate numerical methods,and is orders of magnitude faster than using the mean flow quantities and Reynolds stresses to evaluate solution ***,an hp-refinement study is performed to establish the relative accuracy and efficiency of high-order schemes of various accuracy.

关键词： Large eddy simulation Direct numerical simulation High-order methods Navier-Stokes Taylor Couette flow

来源：

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

Turbulence and mixing in a freshwater-influenced tidal bay: Observations and numerical modeling

引用

Science China Earth Sciences 2015年第7期58卷 2049-2058页

作者： LIAN Qiang LIU z.iYu Department of Physical Oceanography College of Ocean & Earth Sciences Xiamen University State Key Laboratory of Marine Environmental Science Xiamen University

In situ observations and numerical simulations of turbulence are essential to understanding vertical mixing processes and their dynamical controls on both physical and biogeochemical processes in coastal embayments. Using in situ data collected by bottom-mounted acoustic Doppler current profilers(ADCPs) and a free-falling microstructure profiler, as well as numerical simulations with a second-moment turbulence closure model, we studied turbulence and mixing in the Xiamen Bay, a freshwater-influenced tidal bay located at the west coast of the Taiwan Strait. Dynamically, the bay is driven predominantly by the M2 tide, and it is under a significant influence of the freshwater discharged from the Jiulong River. It is found that turbulence quantities such as the production and dissipation rates of the turbulent kinetic energy(TKE) were all subject to significant tidal variations, with a pronounced ebb-flood asymmetry. Turbulence was stronger during flood than ebb. During the flooding period, the whole water column was nearly well mixed with the depth-averaged TKE production rate and vertical eddy viscosity being up to 5?10?6 W kg?1 and 2?10?2 m2 s?1, respectively. In contrast, during the ebb strong turbulence was confined only to a 5?8 m thick bottom boundary layer, where turbulence intensity generally decreases with distance from the seafloor. Diagnosis of the potential energy anomaly showed that the ebb-flood asymmetry in turbulent dissipation and mixing was due mainly to tidal straining process as a result of the interaction between vertically shared tidal currents and horiz.ntal density gradients. The role of vertical mixing in generating the asymmetry was secondary. A direct comparison of the modeled and observed turbulence quantities confirmed the applicability of the second-moment turbulence closure scheme in modeling turbulent processes in this weakly stratified tidally energetic environment, but also pointed out the necessity of further refinements of the model.

关键词： tidal bay turbulent mixing second-moment turbulence closure model turbulent kinetic energy dissipation rate vertical eddy viscosity

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On the mesh resolution of industrial LES based on the DNS of flow over the T106C turbine

引用

Advances in Aerodynamics 2019年第1期1卷 408-425页

作者： Mohammad Alhawwary z.J.Wang Department of Aerospace Engineering University of KansasLawrenceKS66045US

A high-order Navier-Stokes solver based on the flux reconstruction(FR)or the correction procedure via reconstruction(CPR)formulation is employed to perform a direct numerical simulation(DNS)and large eddy simulations(LES)of a well-known benchmark problem–transitional flow over the low-pressure T106C turbine ***-refinement studies are carried out to assess the resolution requirement.A 4th order(p3)simulation on the fine mesh is performed with a DNS resolution to establish a"converged"solution,including the mean pressure and skin-friction distributions,and the power spectral density in the *** LES on the coarse and fine meshes with lower order schemes are conducted to assess the mesh and order dependence of the *** particular,we study the error in the transition location,the mean skin-friction distribution,and the mean lift and drag *** h-and p-refinement studies provide a much-needed guideline in h-and p-resolutions to achieve a certain level of accuracy for industrial LES applications.

关键词： Direct numerical simulations Large eddy simulations Transitional flows High-order FR/CPR T106C Skin-friction

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：