检索结果-南通市图书馆

Prediction of bedload transport inside vegetation canopies with natural morphology

Journal of Hydrodynamics 2024年第3期36卷 556-569页

作者： Li He Yu-qi Shan Chao Liu Hui Cao Xing-nian Liu yakun guo State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China Institute for Disaster Management and Reconstruction Sichuan UniversityChengdu610065China China Yangtze Power Co. Ltd.Yichang443002China Hubei Key Laboratory of Intelligent Yangtze and Hydroelectric Science Yichang443002China Faculty of Engineering and Informatics University of BradfordBradfordUK

Due to vegetation drag and vegetation-generated turbulence,bedload transport in vegetated channels is more complicated than that in nonvegetated *** is challenging to obtain accurate predictions of bedload transport in vegetated *** studies generally used rigid circular cylinders to simulate vegetation,and the impact of plant morphology on bedload transport was typically ignored;these methods deviate from natural scenarios,resulting in prediction errors in transport rates of more than an order of *** study measured bedload transport rates inside ***,*** and *** canopies and in arrays of rigid cylinders for *** impact of plant morphology on bedload transport in vegetated channels was *** the canopies of natural morphology,the primary factor driving bedload transport is the near-bed turbulent kinetic energy(TKE),which consists of both bed-generated and vegetation-generated turbulence.A method was proposed to predict the near-bed TKE inside canopies with natural *** the same solid volume fraction of plants,the transport rate inside canopies with a natural morphology is greater than or equal to that within an array of rigid cylinders,depending on the plant *** finding indicates that plant morphology has a significant impact on transport rates in vegetated regions and cannot be ignored,which is typical in *** classic bedload transport equations(the Meyer-Peter-Müller,Einstein,Engelund and Dou equations),which are suitable for bare channels(no vegetation),were modified in terms of the near-bed *** predicted near-bed TKE was inserted into these four equations to predict the transport rate in canopies with natural morphology.A comparison of the predictions indicated that the Meyer-Peter-Müller equation had the highest accuracy in predicting the transport rate in vegetated landscapes.

关键词： Vegetated landscapes turbulent kinetic energy(TKE) bedload transport plant morphology predictive methods

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

EXPERIMENTAL STUDY ON THE EFFECTS OF AIR ENTRAINMENT ON A PLANE JET DIFFUSION IN A PLUNGE POOL

引用

Journal of Hydrodynamics 1999年第2期11卷 32-37页

作者： guo, yakun Luo, Ming Sichuan univ Chengdu China

Laboratory experimental results about the effects of air entrainment on the jet diffusion in a plunge pool were presented. The results indicate that the air entrainment has little effect on the maximum mean impinging pressure generated by the jet at pool bottom. The maximum fluctuating pressure is increased with the increase of the air entrainment. Air entrainment also reduces jet spreading.

关键词： Air ejectors Energy dissipators Jet engines Jets Pressure effects Pressure measurement Velocity measurement

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

INTRINSIC FEATURES OF TURBULENT FLOW IN STRONGLY 3-D SKEW BLADE PASSAGE OF A FRANCIS TURBINE

引用

Journal of Hydrodynamics 2007年第1期19卷 92-99页

作者： ZHANG Li-xiang WANG Wen-quan guo yakun Department of Engineering Mechanics Kunming University of Science and Technology Kunming 650051 China guo yakun Department of Engineering University of Aberdeen Aberdeen AB24 3UE UK.

The turbulent flow, with the Reynolds number of 5.9×10^5, in the strongly 3-D skew blade passage of a true Francis hydro turbine was simulated by the Large Eddy Simulation （LES） approach to investigate the spatial and temporal distributions of the fully developed turbulence in the passage with strongly 3-D complex geometry. The simulations show that the strong three-dimensionality of the passage has a great amplification effect on the turbulence in the passage, and the distributions of the turbulence are diversely nonuniform, for instance, the rise of turbulent kinetic energy in the lower 1/3 region of the passage is more than 45%, whereas its rise in the upper 1/3 region is less than 1%. With the LES approach, the details of the flow structures at the near-wall surfaces of the blades could be obtained. Several turbulent spots were captured.

关键词： turbulent flow Large Eddy Simulation (LES),hydro turbine

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 FLOW CONSIDERING INFLOW WAKES IN A FRANCIS TURBINE BLADE PASSAGE

引用

Journal of Hydrodynamics 2007年第2期19卷 201-209页

作者： WANG Wen-quan ZHANG Li-xiang YAN Yan guo yakun Department of Engineering Mechanics Kunming University of Science and Technology Kunming 650051 China Department of Engineering University of Aberdeen Aberdeen AB24 3UE UK

Turbulent flow in a 3-D blade passage of a Francis hydro turbine was simulated with the Large Eddy Simulation （LES） to investigate the spatial and temporal distributions of the turbulence when strongly distorted wakes in the inflow sweep over the passage, In a suitable consideration of the energy exchanging mechanism between the large and small scales in the complicated passage with a strong 3-D curvature, one-coefficient dynamic Sub-Grid-Scale （SGS） stress model was used in this article. The simulations show that the strong wakes in the inflow lead to a flow separation at the leading zone of the passage, and to form a primary vortex in the span-wise direction. The primary span-wise vortex evolves and splits into smaller vortex pairs due to the constraint of no-slip wall condition, which triggers losing stability of the flow in the passage. The computed pressures on the pressure and suction sides agree with the measured data for a working test turbine model.

关键词： Large Eddy Simulation (LES) turbulent flow,numerical simulation wakes Francis hydro turbine

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

Investigation of the sediment transport capacity in vegetated open channel flow

引用

Journal of Hydrodynamics 2021年第2期33卷 386-389页

作者： Wen-xin Huai Xiang Wang yakun guo Zhao-hua Sun Zhong-hua Yang State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Faculty of Engineering and Informatics University of BradfordBradfordUK

The suspended sediment transport capacity is important for estimating the suspended load concentration and the ecological environment of the *** far,few studies have been conducted to investigate the suspended sediment transport capacity in the vegetated sediment-laden *** this study,a new formula is derived to predict the sediment transport capacity in a vegetated flow by considering the absolute value of the energy loss between the sediment-laden flow and the clear water ***,the formula is expressed in a practical form by using the logarithmic matching method.

关键词： Sediment transport vegetation suspended sediment concentration

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

Flow turbulence presented by different vegetation spacing sizes within a submerged vegetation patch

引用

Journal of Hydrodynamics 2023年第6期35卷 1131-1145页

作者： Chukwuemeka Kingsley John Jaan H.Pu yakun guo Prashanth R.Hanmaiahgari Manish Pandey Faculty of Engineering and Informatics University of BradfordBradfordUK Department of Civil Engineering Indian Institute of TechnologyKharagpurIndia National Institute of Technology(NIT) WarangalIndia

This study presents results from a vegetation-induced flow experimental study which investigates 3-D turbulence structure profiles,including Reynolds stress,turbulence intensity and bursting analysis of open channel *** vegetation densities have been built between the adjacent vegetations,and the flow measurements are taken using acoustic Doppler velocimeter(ADV)at the locations within and downstream of the vegetation *** different tests are conducted,where the first test has compact vegetations,while the second and the third tests have open spaces created by one and two empty vegetation slots within the vegetated *** reveals that over 10%of eddies size is generated within the vegetated zone of compact vegetations as compared with the fewer *** turbulence structures variation is also observed at the points in the non-vegetated *** findings from burst-cycle analysis show that the sweep and outward interaction events are dominant,where they further increase away from the *** effect of vegetation on the turbulent burst cycle is mostly obvious up to approximately two-third of vegetation height where this phenomenon is also observed for most other turbulent structure.

关键词： Velocity profiles acoustic Doppler velocimeter(ADV) turbulent intensities Reynolds stress turbulent bursting vegetated flow vegetation spacing sizes

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

Investigation of open channel flow with unsubmerged rigid vegetation by the lattice Boltzmann method

引用

Journal of Hydrodynamics 2020年第4期32卷 771-783页

作者： He-fang Jing Yin-juan Cai Wei-hong Wang yakun guo Chun-guang Li Yu-chuan Bai State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300350China Key Laboratory of Intelligent Information and Big Data Processing of Ningxia Province Yinchuan 750021China School of Civil Engineering North Minzu UniversityYinchuan 750021China Faculty of Engineering and Informatics University of BradfordBradfordUK

The aquatic vegetation can significantly affect the flow structure,the sediment transport,the bed scour and the water quality in rivers,lakes,reservoirs and open *** this study,the lattice Boltzmann method(LBM)is applied in the two-dimensional numerical simulation of the flow structure in a flume with rigid vegetation.A multi-relaxation time model is applied to improve the stability of the numerical scheme for flows with a high Reynolds *** vegetation induced drag force is added in the lattice Boltzmann equation model in order to improve the simulation accuracy and an algorithm of the multi-relaxation time is *** simulations are performed for a wide range of flow and vegetation conditions and are validated by comparing with the laboratory *** of the simulated and experimentally measured flow Helds shows that the numerical simulation can satisfactorily reproduce the laboratory experiments,indicating that the proposed lattice Boltzmann model enjoys a high accuracy for simulating the flow-vegetation interaction in open channels.

关键词： Lattice Boltzmann method(LBM) multi-relaxation time model aquatic vegetation drag force open channel 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

Scour Development Around Submarine Pipelines due to Current Based on the Maximum Entropy Theory

引用

Journal of Ocean University of China 2016年第5期15卷 841-846页

作者： ZHANG Jing SHI Bing guo yakun XU Weilin YANG Kejun ZHAO Enjin College of Engineering Ocean University of China School of Engineering University of Bradford State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University

This paper presents the results from laboratory experiments and theoretical analysis to investigate the development of scour around submarine pipeline under steady current conditions. Experiments show that the scour process takes place in two stages: the initial rapid scour and the subsequent gradual scour development stage. An empirical formula for calculating the equilibrium scour depth(the maximum scour depth) is developed by using the regression method. This formula together with the maximum entropy theory can be applied to establish a formula to predict the scour process for given water depth, diameter of pipeline and flow velocity. Good agreement between the predicted and measured scour depth is obtained.

关键词： pipeline calculating entropy subsequent submarine empirical gradual iterative acceleration continuity

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

STUDY ON TURBULENCE FEATURES NEAR AN OSCILLATING CURVED WALL

引用

Journal of Hydrodynamics 2007年第3期19卷 255-263页

作者： WANG Wen-quan ZHANG Li-xiang YAN Yan guo yakun Department of Engineering Mechanics Kunming University of Science and Technology Kunming 650051China Department of Engineering University of Aberdeen Aberdeen AB24 3UE UK

In pursuit of possibly true turbulent characters and for exploring a change in turbulence structures near an oscillating flexible wall-curved surface, a sinusoidal oscillation mode was forced to a curved wall, whose vibrations disturbed the flow with an interacting effort between the fluid and the structure. The methodology used was the Large Eddy Simulation （LES） with fluid-structure interaction. The oscillating configuration was on a Fourier sinusoidal mode from the measurements of a Francis hydro turbine blade vibration. The effects of the vibration on the skin friction coefficient, vortices, turbulent coherent structures, and other statistical quantities were studied. The results showed that the streamwise velocity gradient along the normal direction and the normal velocity gradient along the spanwise direction were considerably increased within the viscous sublayer because of the oscillating wall, which additionally caused the low speed streaks to stay away from the wall and the high-momentum flows to be toward the wall. As a result, the streamwise vortices were much more elongated along the downstream to get an energy balance, and the wall skin friction coefficient or the wall friction velocity rose up.

关键词： turbulent flow turbulent structure Large-Eddy Simulation (LES) fluid-structure interaction

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 investigation on critical length of impermeable plate below underwater pipeline under steady current

引用

Science China(Technological Sciences) 2013年第6期56卷 1232-1240页

作者： ZHANG ZhiYong SHI Bing guo yakun YANG LiPeng College of Engineering Ocean University of China School of Engineering University of Aberdeen

This study proposes a new approach in which an impermeable plate is placed under the pipeline to prevent the local scour around the *** order to understand the performance of this approach,the finite volume method(FVM) and volume of fluid(VOF) method are adopted to simulate the flow field around the *** pressure distribution along the sandy bed surface is obtained by considering the variation of water ***,the effects of water depth,unidirectional and bidirectional impermeable plates on pressure difference are *** seepage flow field of sandy bed near underwater pipeline is numerically simulated using the laminar and porous media *** this basis,the effect of the impermeable plate length on hydraulic gradient is investigated and the critical length of impermeable plate is *** simulated results show that when the water depth is smaller than 5.00D(D is the diameter of pipeline),the effect of the water depth on the pressure difference is *** pressure differences between two endpoints of both the unidirectional and bidirectional plates decrease with the increase of the plate *** variations of the pressure differences for both the unidirectional and bidirectional plates are *** the increase of plate length,the hydraulic gradient decreases and the piping at the seepage exit is avoided effectively as long as it reaches a certain *** a critical length of the plate decreases with the increase of the water *** water depth is larger than 4.00D,the effect of the water depth on the critical length is *** the same water depth,the critical length of impermeable plate increases with the increase of the dimensionless flow *** simulation results are in good agreement with the available experimental measurements.

关键词： underwater pipeline steady current impermeable plate numerical simulation critical length

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

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：