检索结果-南通市图书馆

Effect of Stokes number on energy modulation of the fluid in turbulent particle-laden channel flows

Journal of Hydrodynamics 2022年第3期34卷 510-521页

作者： zhi-feng Wu Jian-zhao Wu Bo-fu Wang zhi-ming lu Shanghai Institute of Applied Mathematics and Mechanics School of Mechanics and Engineering ScienceShanghai Key Laboratory of Mechanics in Energy EngineeringShanghai UniversityShanghai200072China

The effect of Stokes number on the kinetic energy(KE)budget in particle-laden turbulent channel flows is examined by conducting two-way coupled direct numerical simulations using the Eulerian-Lagrangian *** friction Reynolds number of the single phase channel flow is Re_(τ)=180,the particle mass loading and volume fraction areφ_(m)=0.2,φ_(v)≈10−4,and the Stokes numbers range from St^(+)=14–*** statistics show that due to the presence of solid particles,the mean velocity is reduced in the vicinity of the wall but enhanced in the outer region,and the off-streamwise intensity of fluctuated velocity and the Reynolds stress are reduced in the whole *** analysis on the budgets of turbulent kinetic energy(TKE)finds that the presence of particles induces a significant reduction on both the production and dissipation *** increasing Stokes number St^(+),both the production and dissipation rates exhibit non-monotonical trends,i.e.,both initially decrease for St^(+)*** suggests that the particle-induced suppression on TKE production and dissipation is the strongest nearly at St^(+)=*** is also found that particles act as an additional sink/source term in the budgets of both mean-flow kinetic energy(MKE)and *** addition,we investigate the influence of St^(+)on the“zero point”which indicates the balance of exchanging energy between the particle and fluid *** is shown that with increasing St^(+),the“zero point”moves toward the wall,suggesting that the position of perfect following between particle and fluid is closer to the wall with larger St^(+).The present results reveal the Stokes number effects on the spatial transport mechanisms of MKE,TKE in turbulent channel flows laden with inertial particles.

关键词： Particle-laden flows two-way coupling Stokes numbers kinetic energy budgets

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

SIMULATION OF LAGRANGIAN DISPERSION USING A LAGRANGIAN STOCHASTIC MODEL AND DNS IN A TURBULENT CHANNEL FLOW

引用

Journal of Hydrodynamics 2009年第6期21卷 767-773页

作者： luO Jian-ping lu zhi-ming LIU Yu-lu School of Mechanical and Automation Engineering Shanghai Institute of Technology Shanghai 200235 China Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China

The mean square displacements of fluid particles in a turbulent channel flow at Reτ = 100 are investigated using a modified Langevin equation, and are compared with DNS results. Both the Lagrangian integral time scales directly obtained from DNS and the predicted values using an empirical relation between the Eulerian and the Lagrangian integral time scales are used in the modified Langevin equation to test the effects of integral time scales on the dispersion of particles. The results show that the slight variation of the Lagrangian integral time scale has little influence on the dispersion. The agreement between results of the model equation and those of DNS is satisfactory except the streamwise dispersion for intermediate times （ 20 〈 t^＋〈 300 ）, where the results of the model equation are slightly overestimated compared to those of DNS. The cause of such discrepancy is discussed.

关键词： turbulent channel flow Lagrangian dispersion Lagrangian stochastic model

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 boundary layer flow over multiple hills

引用

Journal of Hydrodynamics 2023年第4期35卷 746-756页

作者： Ying Deng Kai Leong Chong Yan Li zhi-ming lu Bo-fu Wang Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai200072China School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai200092China

Atmospheric boundary layer(ABL)flow over multiple-hill terrain is studied *** spectral vanishing viscosity(SVV)method is employed for implicit large eddy simulation(ILES).ABL flow over one hill,double hills,and three hills are presented in *** instantaneous three-dimensional vortex structures,mean velocity,and turbulence intensity in mainstream and vertical directions around the hills are investigated to reveal the main properties of this turbulent *** the flow evolution downstream,the Kelvin-Helmholtz vortex,braid vortex,and hairpin vortex are observed *** turbulence intensity is enhanced around crests and reduced in the recirculation *** present results are helpful for understanding the impact of topography on the turbulent *** findings can be useful in various fields,such as wind energy,air pollution,and weather forecasting.

关键词： Large-eddy simulation(LES) atmospheric boundary layer(ABL)flow complex terrain turbulent flow fields

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

TURBULENT MIXING AND EVOluTION IN A STABLY STRATIFIED FLOW WITH A TEMPERATURE STEP

引用

Journal of Hydrodynamics 2009年第1期21卷 84-92页

作者： QIU Xiang ZHANG Dao-xiang lu zhi-ming LIU Yu-lu Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China Department of Mathematics Shanghai University Shanghai 200444 China

Large-Eddy Simulation （LES） is applied to examine the turbulent mixing and evolution in a stably stratified flow with a thermally sharp interface. Turbulent velocity intensities and turbulent kinetic energy are analyzed by considering the mean shear and stratification effects. The evolution of turbulent mixing layer and turbulent structures are mainly investigated. The results show that the streamwise intensities are much larger than the vertical intensities, and vertical fluctuations decay more rapidly at the presence of stratification. The qualitatively computational results suggest that the mixing layer, defined by the mean temperature, inclines to the side with small inlet velocity. The evolution of the half-width of the mixing layer shows two different slopes. The turbulent structure with high vorticity is restricted in the mixing layer especially in strong stratified cases.

关键词： stratified turbulence turbulent mixing turbulent structure Large-Eddy Simulation (LES)

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

NUMERICAL SIMULATION OF THE DISPERSION IN OSCILLATING FLOWS WITH REVERSIBLE AND IRREVERSIBLE WALL REACTIONS

引用

Journal of Hydrodynamics 2009年第4期21卷 482-490页

作者： ZHANG Dao-xiang lu zhi-ming LIU Yu-lu NG Chiu-On Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China College of Mathematics and Computer Science Anhui Normal University Wuhu 241000 China Department of Mechanical Engineering The University of Hong Kong Hong Kong China

This is a study on the mass transport of a solute or contaminant in oscillating flows through a circular tube with a reactive wall layer. The reaction consists of a reversible component due to phase exchange between the flowing fluid and the wall layer, and an irreversible component due to absorption into the wall. The short-time dispersion characteristics are numerically investigated, incorporating the coupling effects between the flow oscillation, sorption kinetics, and retardation due to phase partitioning. The effects of various dimensionless parameters e.g., Da （the Damkoehler number）, α （phase partitioning number）, F （dimensionless absorption number）, and δ （dimensionless Stokes boundary layer number） on dispersion are discussed. In particular, it is found that there exist trinal peaks of the breakthrough curves in some cases.

关键词： dispersion flow oscillation wall reactions

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

Toward a Direct Measurement of the Cosmic Acceleration:The Pilot Observation of HI 21 cm Absorption Line at FAST

引用

Research in Astronomy and Astrophysics 2024年第7期24卷 47-55页

作者： Jiangang Kang Chang-zhi lu Tong-Jie Zhang ming Zhu Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China School of Physics and Astronomy Beijing Normal UniversityBeijing 100875China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China

This study presents results on detecting neutral atomic hydrogen(H I)21 cm absorption in the spectrum of PKS PKS1413+13 at redshift z=*** observation was conducted by FAST,with a spectral resolution of10 Hz,using 10 minutes of observing *** global spectral profile is examined by modeling the absorption line using a single Gaussian function with a resolution of 10 kHz within a 2 MHz *** goal is to determine the rate of the latest cosmic acceleration by directly measuring the redshift evolution of the H I 21 cm absorption line with Hubble flow toward a common background quasar over a decade or longer time *** will serve as a detectable signal generated by the accelerated expansion of the Universe at redshift zlumn density in this DLA system is approximately equivalent to the initial observation value,considering uncertainties of the spin temperature of a spiral host *** high signal-to-noise ratio of 57,obtained at a 10 kHz resolution,strongly supports the feasibility of using the H I 21 cm absorption line in DLA systems to accurately measure the redshift drift rate at a precision level of around 10~(-10)per decade.

关键词： (cosmology)cosmological parameters-cosmology observations-cosmology theory-(cosmology)dark energy-radio lines ISM-radio lines galaxies-ISM clouds

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

Helicobacter pylori intragastric colonization and migration:Endoscopic manifestations and potential mechanisms

引用

World Journal of Gastroenterology 2023年第30期29卷 4616-4627页

作者： Tong Mu zhi-ming lu Wen-Wen Wang Hua Feng Yan Jin Qian Ding Li-Fen Wang Department of Gastroenterology Shandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinan 250021Shandong ProvinceChina Department of Clinical Laboratory Medicine Shandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinan 250021Shandong ProvinceChina

After being ingested and entering the human stomach,Helicobacter pylori(***)adopts several effective strategies to adhere to and colonize the gastric mucosa and move to different regions of the stomach to obtain more nutrients and escape from the harsher environments of the stomach,leading to acute infection and chronic gastritis,which is the basis of malignant gastric *** endoscopic manifestations and pathological features of *** infection are diverse and vary with the duration of *** this review,we describe the endoscopic manifestations of each stage of *** gastritis and then reveal the potential mechanisms of bacterial intragastric colonization and migration from the perspective of endoscopists to provide direction for future research on the effective therapy and management of *** infection.

关键词： Helicobacter pylori Colonization Endoscopy Gastritis Infection

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

引用

Applied Mathematics and Mechanics(English Edition) 2014年第11期35卷 1353-1360页

作者：杨曼丽卢志明刘宇陆 Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University Tianmu College Zhejiang Agriculture and Forestry University

Self-similar behavior for the multicomponent coagulation system is investigated analytically in this paper. Asymptotic self-similar solutions for the constant kernel, sum kernel, and product kernel are achieved by introduction of different generating functions. In these solutions, two size-scale variables are introduced to characterize the asymptotic distribution of total mass and individual masses. The result of product kernel （gelling kernel） is consistent with the Vigli-Ziff conjecture to some extent. Furthermore, the steady-state solution with injection for the constant kernel is obtained, which is again the product of a normal distribution and the scaling solution for the single variable coagulation.

关键词： multicomponent coagulation self-similar solution generating function

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

Inhibition of viability of human retinal microvascular endothelial cells by vialinin A under high glucose condition

引用

International Journal of Ophthalmology(English edition) 2024年第10期17卷 1809-1815页

作者： zhi-Gang Chen Gao-Qin Liu Wei-ming Liu Pei-Rong lu Department of Ophthalmology the First Affiliated Hospital of Soochow UniversitySuzhou 215006Jiangsu ProvinceChina Jiangsu Clinical Immunology Institute the First Affiliated Hospital of Soochow UniversitySuzhou 215006Jiangsu ProvinceChina

AIM:To investigate the effects of vialinin A on viability of human retinal endothelial cells(HRECs)under high glucose condition and its potential ***:The HRECs were divided into four groups:normal glucose control group(NG,5 mmol/L D-glucose),high glucose group(HG,30 mmol/L D-glucose),HG+1μmol/L vialinin A group,and HG+5μmol/L vialinin A *** cell viabilities were measured with cell counting kit-8(CCK-8)assay for proliferation,with scratch assay for migration,and tube formation,for evaluation of the impact of vialinin A on cellular ***-time PCR and Western blotting were used to determine the expression level of vascular endothelial growth factor(VEGF).RESULTS:The proliferative capacity and migration of HRECs was reduced by 5μmol/L vialinin A in high glucose environment(both Plucose-induced tube formation of *** expression level of VEGF and PI3K in HRECs was also significantly decreased by vialinin A(PluSION:Vialinin A inhibits the cell viability of *** may serve as a potential target for anti-angiogenic therapy.

关键词： vialinin A vascular endothelial growth factor human retinal endothelial cells cell viability

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

The Contribution of United States Aircraft Reconnaissance Data to the China Meteorological Administration Tropical Cyclone Intensity Data:An Evaluation of Homogeneity

引用

Advances in Atmospheric Sciences 2024年第4期41卷 639-654页

作者： ming YING Xiaoqin lu Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030China

This paper investigates the homogeneity of United States aircraft reconnaissance data and the impact of these data on the homogeneity of the tropical cyclone(TC)best track data for the seasons 1949-1987 generated by the China Meteorological Administration(CMA).The evaluation of the reconnaissance data shows that the minimum central sea level pressure(MCP)data are relatively homogeneous,whereas the maximum sustained wind(MSW)data show both overestimations and spurious abrupt *** comparisons suggest that both the reconnaissance MCP and MSW were well incorporated into the CMA TC best track *** no spurious abrupt changes were evident in the reconnaissance-related best track MCP data,two spurious changepoints were identified in the remainder of the best-track MCP ***,the influence of the reconnaissance MSWs seems to extend to the best track MSWs unrelated to reconnaissance,which might reflect the optimistic confidence in making higher estimates due to the overestimated extreme wind“observations”.In addition,the overestimation of either the reconnaissance MSWs or the best track MSWs was greater during the early decades compared to later decades,which reflects the important influence of reconnaissance data on the CMA TC best track *** wind-pressure relationship(WPR)used in the CMA TC best track dataset is also evaluated and is found to overestimate the MSW,which may lead to inhomogeneity within the dataset between the aircraft reconnaissance era and the satellite era.

关键词： tropical cyclone intensity homogeneity best track aircraft reconnaissance

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

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：