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NUMERICAL SIMULATION OF THE ENERGY DISSIPATION CHARACTERISTICS IN STILLING BASIN OF MULTI-HORIZONTAL SUBMERGED JETS

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Journal of Hydrodynamics 2010年第5期22卷 732-741页

作者： CHEN Jian-gang ZHANG Jian-min XU Wei-lin WANG Yu-rong state key laboratory of hydraulics and Mountain River Engineering Sichuan University Chengdu 610065 China

3-D numerical simulation was carried out for the water flow in a stilling basin with multi-horizontal submerged jets by using two different turbulence models, namely, the VOF RNG k-ε and Mixture RNG k-ε turbulence models. The calculated water depth, velocity profile and pressure distribution are in good agreement with the data obtained in experiments. It indicates that the numerical simulation can effectively be used to study the water flow movement and the energy dissipation mechanism. The numerical simulation results show that the turbulent kinetic energy distribution obtained by using the Mixture turbulence model covers a region about 18% larger than that calculated by using the VOF turbulence model, and is in better agreement with the actual situation. Furthermore, the Mixture turbulence model is better than the VOF turbulence model in calculating the air entrainment.

关键词： multi-horizontal submerged jets numerical simulation VOF method Mixture method hydraulic characteristics stilling basin

THREE-DIMENSIONAL NUMERICAL SIMULATION OF AERATED FLOWS DOWNSTREAM SUDDEN FALL AERATOR EXPANSION-IN A TUNNEL

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Journal of Hydrodynamics 2011年第1期23卷 71-80页

作者： ZHANG Jian-min CHEN Jian-gang XU Wei-lin WANG Yu-rong LI Gui-ji state key laboratory of hydraulics and Mountain River Engineering Sichuan University Chengdu 610065China

Air entrainment is known to be one of efficient and inexpensive methods to prevent cavitation damages in hydropower *** shape of sudden expansion-fall is used as a common device for mitigating cavitation *** complex flow patterns with cavitation are numerically simulated by using the realizable k-εturbulence model and the air-water mixture *** calculated results are compared well with the experimental results as well as those obtained with the k-εturbulence model with the Volume Of Fluid（VOF）*** calculated results agree well with the experimental data for the aeration cavity and wall ***,the air concentration near sidewall is simulated by a mixture *** is found that the mixture turbulence model is superior to the VOF turbulence model.

关键词： sudden expansion-fall aerator RNG k-εturbulence model realizable k-εturbulence model Volume Of Fluid (VOF)method air-water Mixture turbulence model numerical simulation

Air concentration distribution in the impact zone of spillway aerator

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Journal of Hydrodynamics 2022年第1期34卷 156-161页

作者： Rui-di Bai Fa-xing Zhang Wei Wang Shan-jun Liu state key laboratory of hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China

The chute aerators separate the flow from the chute bottom,and the violent turbulence is generated after the flow impacts the *** the chute aerators were widely investigated experimentally,the air concentration distribution of the lower jet in the impact zone remains to be explored *** the impact zone,it is observed that a portion of the air stays in the rollers instead of traveling with the flow,decreasing the air transportation *** on extensive tests,a comprehensive formula is developed to compute the air concentration distribution in the impact zone,with results in good agreement with the model tests.

关键词： Chute aerator impact zone air concentration cavity length experimental data

Velocity and turbulence characteristics in an open channel with multi-row staggered vegetation patches

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Journal of Hydrodynamics 2021年第5期33卷 1035-1044页

作者： Hong-sheng Fu Dan Wang Wen-qi Li Bao-liang Ren Ke-jun Yang state key laboratory of hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China

A staggered distribution of vegetation is very common in nature,which might significantly affect the flow *** investigate its impact,three rows of staggered vegetation groups are designed under seven different working *** horizontal and vertical distances between the vegetation groups are constant,while the vegetation density is *** flow field is measured by the acoustic Doppler velocimeter(ADV).It is indicated that both the patch exit velocity and the steady wake velocity decrease with the increase of the density,which is also related to the vegetation *** for the first patch,the upstream adjustment regions of all patches are diminished to some extent,due to the effect of the contralateral *** steady wake region also shows a decreasing trend,with a reduction of 0.5D each time when the water flows through the *** means that the flow structure is also affected by the number of vegetation *** intensity of the turbulence increases along the channel and has a non-axisymmetric distribution similar to that of the *** Karman vortex street generated by the patches on the same side would merge into a larger vortex *** on its intensity,the vegetation at the back has different effects on the vortex street.

关键词： Velocity turbulence intensity staggered vegetation patches Karman vortex street open channel

Air entrainment and detrainment downstream a chute aerator

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Journal of Hydrodynamics 2019年第1期31卷 76-82页

作者： Rui-di Bai Fa-xing Zhang Wei Wang Shan-jun Liu state key laboratory of hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China

The chute aerators separate the flow from the chute bottom,and the air can enter into the flow through the lower *** this study,the air concentration and the pressure along the chute bottom are investigated systematically by a series of model tests with the upper aeration effect being *** chute downstream the aerator is partitioned into four zones:the cavity zone,the impact zone,the equilibrium zone,and the far *** is found that a large amount of air entrained in the cavity zone is only partially entrained into the flow ***,the lower air discharge is decreased sharply in the impact zone,and the detrainment disappearsonthe section of x= *** the equilibrium zone,the lower air discharge is kept *** the in crease of the flow Froude number and withthe other parameters kept unchanged,it is found that the dimensionless value of K has a significant ***,a formula to calculate K is proposed,with results in good agreement with the model and prototype data.

关键词： Chute aerator air concentration entrainment detrainment

Experimental study of air-water interface properties in self-aerated flows

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Journal of Hydrodynamics 2019年第5期31卷 940-948页

作者： Wang-ru Wei Wei-lin Xu Jun Deng Zhong Tian Fa-xing Zhang state key laboratory of hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China

The microscopic air-water structures and the interface area properties in the self-aerated flows are important research issues in the high-speed self-aerated *** present experimental study concerns the mean and medium air chord length distributions in the self-aerated chute flows for different flow Reynolds numbers and air concentration *** relationship between the microscopic and the macroscopic aerated properties in the air-water mixture region is *** distribution of the microscopic specific air-water interface area with the macroscopic air concentration variation is self-similar in the self-aerated *** view of the difference of the air-water structure in high and low aerated regions,a new relationship is proposed for predicting the distributions of a specific air-water interface area,and the agreement between the measured and predicted results is satisfactory.

关键词： Air-water interface area self-aeration air chord size chute flow experimental study

Study on resistance coefficient in compound channels

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Acta Mechanica Sinica 2005年第4期21卷 353-361页

作者： Kejun Yang Shuyou Cao Xingnian Liu state key laboratory of hydraulics on High Speed Flows Sichuan University Chengdu 610065 China

This paper presents a further study of the Manning and Darcy-Weisbach resistance coefficients, as they play a significant role in assessing the cross-sectional mean velocity, conveyance capacity and determining the lateral distribution of depth mean velocity and local boundary shear stress in compound channels. The relationships between the local, zonal and overall resistance coefficients, and a wide range of geometries and different roughness between the main channel and the flood plain are established by analyzing a vast amount of experimental data from a British Science and Engineering Research Council Flood Channel Facility （SERC-FCF）. And the experimental results also show that the overall Darcy-Weisbach resistance coefficient for a compound channel is the function of Reynolds number, but the function relationship is different from that for a single channel. By comparing and analyzing the conventional methods with the experimental data to predict composite roughness in compound channels, it is found that these methods are not suitable for compound channels. Moreover, the reason why the conventional methods cannot assess correctly the conveyance capacity of compound channels is also analyzed in this paper.

关键词： Resistance coefficient ,Compound channels,Geometries Roughness Reynolds number Computational methods for composite roughness

Local hydraulic jump effects on sediment deposition in open-channel flume experiments

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Journal of Hydrodynamics 2023年第2期35卷 268-277页

作者： Shi-hao Fu Mao-lin Zhou Wei-lin Xu Wang-ru Wei Guo-guang Wang state key laboratory of hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China

When a river channel is narrow,bifurcated,or intersected,or when extreme weather or geological disasters cause shed rock masses to occupy a river flood channel,local hydraulic jumps may develop in the *** disasters such as landslides,floods,and debris flows occur upstream,will result in large transport rate of large-sized gravel *** particles may be blocked in hydraulic jump areas,causing river channel water depth to *** this study,the effect of local hydraulic jumps on the sediment deposition rate was investigated in flume *** ratio of upstream and downstream Froude numbers,particle size,Sediment supply intensity,and flow discharge all affected the sediment deposition *** increases in the ratio of upstream and downstream Froude numbers,particle size,and sediment supply intensity,the sediment deposition rate *** sediment deposition rate decreased with an increase in flow *** hydraulic conditions and particle properties jointly determined the sediment deposition rate in a hydraulic jump section,and an empirical formula was developed using those parameters to calculate the sediment deposition ***,to identify risks and prevent disasters in mountain rivers,local changes in hydraulic conditions and particle properties need to be jointly evaluated.

关键词： Hydraulic jump sediment deposition particle size upstream/downstream Froude numbers ratio sediment supply intensity flowdischarge

Collapsing characteristics of gas-bearing cavitation bubble

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Journal of Hydrodynamics 2019年第1期31卷 66-75页

作者： Ya-lei Zhang Wei-lin Xu Fa-xing Zhang Qi Zhang state key laboratory of hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China

The cavitation is directly related to the safety of many large water conservancy *** are two types of cavitation bubbles,one is generated by the gas nucleus,called the non gas-bearing cavitation bubble,and another is generated by the gas bubble,called the gas-bearing cavitation *** have significantly different collapsing *** paper studies the cavitation bubbles,generated by a high voltage pulse bubble generation system,and discusses the gas-bearing cavitation bubble's characteristics a from the aspects of the collapse process,the cycle,the size and the collapse *** is shown that:(1) the collapse of the gas-bearing cavitation bubbles can be divided into two types:the centripetal collapse and the bisected collapse,(2) the cycle period and the size of the gas-bearing cavitation bubble increase significantly,and the increase norm has a certain relationship with the bubble diameter ratio,(3) the collapse strength of the gas-bearing cavitation bubble decreases *** larger the bubble diameter ratio,the greater the effect will be.

关键词： Cavitation gas-bearing cavitation bubble collapse cycle collapse strength