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Prof. Dr. Xiekang Wang
State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China

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Research Keywords & Expertise

0 Flash flood
0 Hydraulics and River Dynamics
0 Water–sediment disaster
0 Forecasting and early warning
0 Hydrological–hydrodynamic modeling

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Journal article
Published: 31 December 2020 in Water
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After the 2008 Mw 7.9 Wenchuan earthquake, geological hazards occurred frequently in the southwest mountainous watershed. Frequent landslide disasters provide abundant sediment supply for mountain torrent disasters. The estimation of the potential landslide volume is essential for the risk assessment of mountain torrent disasters. In this study, a method of calculation that combines TRIGRS and the slope-units for estimating the landslide volume of a small mountainous watershed has been established. TRIGRS analyzes the watershed landslide safety factor under rainfall conditions based on grid-cells. The slope-units extract the results and combine the empirical power law formula to calculate the potential landslide volume. In this paper, we use this method to assess the landslide volume of the Longxi river basin. The results show that the area and volume estimates of the landslides are consistent with the results observed from satellite images and field surveys. This method can be used to study the impact of sediment transport on mountain torrent disasters in the basin. With different moisture content conditions, the results show that the soil moisture content and slope angle significantly affect the distribution and volume of potential landslides in the watershed, giving rise to the uncertainty of the landslide estimation.

ACS Style

Tong Sun; Zhiyuan Deng; Zexing Xu; Xiekang Wang. Volume Estimation of Landslide Affected Soil Moisture Using TRIGRS: A Case Study of Longxi River Small Watershed in Wenchuan Earthquake Zone, China. Water 2020, 13, 71 .

AMA Style

Tong Sun, Zhiyuan Deng, Zexing Xu, Xiekang Wang. Volume Estimation of Landslide Affected Soil Moisture Using TRIGRS: A Case Study of Longxi River Small Watershed in Wenchuan Earthquake Zone, China. Water. 2020; 13 (1):71.

Chicago/Turabian Style

Tong Sun; Zhiyuan Deng; Zexing Xu; Xiekang Wang. 2020. "Volume Estimation of Landslide Affected Soil Moisture Using TRIGRS: A Case Study of Longxi River Small Watershed in Wenchuan Earthquake Zone, China." Water 13, no. 1: 71.

Original paper
Published: 01 October 2020 in Arabian Journal of Geosciences
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After the 2008 Ms 8.0 Wenchuan earthquake, a huge amount of loose debris materials were accumulated on the surface of slopes in the mountainous areas of Southwestern China. Under heavy rainfalls and earthquakes, these loose debris materials can flow, washed away, and subsequently enter the mountainous rivers due to landslides and debris flows. They can change the sediment supply of the river channel and result in the adjustment of riverbed. To mitigate the adverse impacts, baffles are usually installed on slopes in front of the protected areas to reduce the kinetic energy of incoming debris flows. In order to clarify the interacting mechanism between debris materials and baffles structure, the dynamics of granular transportation and deposition in a typical gully have been analyzed via the three-dimensional discrete element method (DEM). The numerical results indicate that the arrangement of baffles (e.g., spacing distance, layout row, and height) has a significant influence on the dissipation of debris energy and the final sediment deposition pattern. The kinetic energy, the velocity of granular flow, and the total mass of debris materials entering the river channel decrease with the increase of the baffles lateral spacing distance, layout row, and height. Correspondingly, the amount of debris materials retained by the baffles will increase. Thickness and volume of particle deposits in the upstream region increased with increase in lateral spacing, rows, and height of the baffles, but decreased in the downstream area. In addition, the baffle configuration can affect the particle size distribution along the channel. The results of this research can provide a theoretical basis for baffle designs and the prevention of debris flows in mountainous areas.

ACS Style

Ming Lei; Po Yang; Yi-Kui Wang; Xie-Kang Wang. Numerical analyses of the influence of baffles on the dynamics of debris flow in a gully. Arabian Journal of Geosciences 2020, 13, 1 -15.

AMA Style

Ming Lei, Po Yang, Yi-Kui Wang, Xie-Kang Wang. Numerical analyses of the influence of baffles on the dynamics of debris flow in a gully. Arabian Journal of Geosciences. 2020; 13 (19):1-15.

Chicago/Turabian Style

Ming Lei; Po Yang; Yi-Kui Wang; Xie-Kang Wang. 2020. "Numerical analyses of the influence of baffles on the dynamics of debris flow in a gully." Arabian Journal of Geosciences 13, no. 19: 1-15.

Journal article
Published: 16 January 2020 in Water
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Flash floods in mountainous areas have become more severe and frequent as a result of climate change and are a threat to public safety and social development. This study explores the application of distributed hydrological models in flash floods risk management in a small watershed in Sichuan Province, China, and aims to increase early warning lead time in mountainous areas. The Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) model was used to simulate the flash flood process and analyze the variation in flood hydrographs. First, the HEC-HMS model was established based on geospatial data and the river network shape, and eight heavy rainfall events from 2010 to 2015 were used for model calibration and validation, showing that the HEC-HMS model was effective for the simulation of mountain floods in the study area. Second, with the assumption that rainfall and flood events have the same frequency, the flood hydrographs with different frequencies (p = 1%, 2%, 5%, and 10%) were calculated by the HEC-HMS model. The rising limbs of the flood hydrographs were significantly different and can be divided into three parts (0–5 h, 6–10 h, and 11–15 h). The rising rate of the flood stage for each part of the flood hydrograph increases in multiples. According to the analysis of the flood hydrographs, two critical early warning indicators with an invention patent were determined in the study: the flood stage for immediate evacuation and the rising rate. The application of the indicators in the study shows that it is feasible to advance the time of issuing an early warning signal, and it is expected that the indicators can offer a reference for flash flood early warning in the study area and other small watersheds in mountainous areas.

ACS Style

Huawei Tu; Xiekang Wang; Wanshun Zhang; Hong Peng; Qian Ke; Xiaomin Chen. Flash Flood Early Warning Coupled with Hydrological Simulation and the Rising Rate of the Flood Stage in a Mountainous Small Watershed in Sichuan Province, China. Water 2020, 12, 255 .

AMA Style

Huawei Tu, Xiekang Wang, Wanshun Zhang, Hong Peng, Qian Ke, Xiaomin Chen. Flash Flood Early Warning Coupled with Hydrological Simulation and the Rising Rate of the Flood Stage in a Mountainous Small Watershed in Sichuan Province, China. Water. 2020; 12 (1):255.

Chicago/Turabian Style

Huawei Tu; Xiekang Wang; Wanshun Zhang; Hong Peng; Qian Ke; Xiaomin Chen. 2020. "Flash Flood Early Warning Coupled with Hydrological Simulation and the Rising Rate of the Flood Stage in a Mountainous Small Watershed in Sichuan Province, China." Water 12, no. 1: 255.

Journal article
Published: 14 January 2020 in Landslides
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ACS Style

Hai-Bo Li; Yue-Ren Xu; Jia-Wen Zhou; Xie-Kang Wang; Hiromitsu Yamagishi; Jie Dou. Preliminary analyses of a catastrophic landslide occurred on July 23, 2019, in Guizhou Province, China. Landslides 2020, 17, 719 -724.

AMA Style

Hai-Bo Li, Yue-Ren Xu, Jia-Wen Zhou, Xie-Kang Wang, Hiromitsu Yamagishi, Jie Dou. Preliminary analyses of a catastrophic landslide occurred on July 23, 2019, in Guizhou Province, China. Landslides. 2020; 17 (3):719-724.

Chicago/Turabian Style

Hai-Bo Li; Yue-Ren Xu; Jia-Wen Zhou; Xie-Kang Wang; Hiromitsu Yamagishi; Jie Dou. 2020. "Preliminary analyses of a catastrophic landslide occurred on July 23, 2019, in Guizhou Province, China." Landslides 17, no. 3: 719-724.

Original paper
Published: 09 January 2020 in Arabian Journal of Geosciences
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The impact of particles on slope bed is not only one of the main processes of eolian saltation, but also lead to the sand surface damage and provide sufficient materials for the sediment supply process in desert rivers. In order to reveal the mechanism of excessive sediment supply in desert rivers, it is necessary to study the grain-bed impact process, which plays an important role on the wind erosion. In this study, based on the discrete element method (DEM) and previous researches, a three-dimensional numerical simulation is carried out to study the influence of the incident angle, incident angle, and lateral incident angle on grain-bed collision under different bed surfaces. Finally, by fitting the simulation data, we give the three-dimensional splash function of ejection velocity, ejection angle, and lateral ejection angle as well as lateral ejection velocity with the change of impact velocity, impact angle, and lateral impact angle on different bed surface. This study will enhance our understanding of the processes of eolian sand movement and will provide useful information about the mechanisms that drive sediment replenishment to desert rivers.

ACS Style

Ming Lei; Ze-Xing Xu; Yi-Kui Wang; Xie-Kang Wang. Dynamic mechanism of three-dimensional mixed-size grain/bed collision on non-flat bed using discrete element method. Arabian Journal of Geosciences 2020, 13, 71 .

AMA Style

Ming Lei, Ze-Xing Xu, Yi-Kui Wang, Xie-Kang Wang. Dynamic mechanism of three-dimensional mixed-size grain/bed collision on non-flat bed using discrete element method. Arabian Journal of Geosciences. 2020; 13 (2):71.

Chicago/Turabian Style

Ming Lei; Ze-Xing Xu; Yi-Kui Wang; Xie-Kang Wang. 2020. "Dynamic mechanism of three-dimensional mixed-size grain/bed collision on non-flat bed using discrete element method." Arabian Journal of Geosciences 13, no. 2: 71.

Journal article
Published: 24 October 2019 in Hydrological Sciences Journal
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ACS Style

Xiekang Wang; Xufeng Yan; Huanfeng Duan; Xingnian Liu; Er Huang. Experimental study on the influence of river flow confluences on the open channel stage–discharge relationship. Hydrological Sciences Journal 2019, 64, 2025 -2039.

AMA Style

Xiekang Wang, Xufeng Yan, Huanfeng Duan, Xingnian Liu, Er Huang. Experimental study on the influence of river flow confluences on the open channel stage–discharge relationship. Hydrological Sciences Journal. 2019; 64 (16):2025-2039.

Chicago/Turabian Style

Xiekang Wang; Xufeng Yan; Huanfeng Duan; Xingnian Liu; Er Huang. 2019. "Experimental study on the influence of river flow confluences on the open channel stage–discharge relationship." Hydrological Sciences Journal 64, no. 16: 2025-2039.

Article
Published: 13 June 2019 in Journal of Mountain Science
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A large amount of loose debris materials were deposited on the slope of mountainous areas after the 2008 Ms 8.0 Wenchuan earthquake. During and after the earthquake, these loose debris deposits collapsed and slide into valleys or rivers, changing river sediment supply condition and channel morphology. To investigate the mechanisms of granular flow and deposition, the dynamics of slope failure and sediment transportation in typical mountainous rivers of different intersection angles were analyzed with a coupling model of Computational Fluid Dynamics and Discrete Element Method (CFD-DEM). The numerical results show that the change of intersection angle between the granular flow flume and the river channel can affect the deposit geometry and the fluid flow field significantly. As the intersection angle increases, the granular velocity perpendicular to the river channel increases, while the granular velocity parallel to the river channel decreases gradually. Compared to the test of dry granular flow, the CFD-DEM coupling tests show much higher granular velocity and larger volume of sediments entrained in the river. Due to the river flow, particles located at the edge of the deposition will move downstream gradually and the main section of sediments deposition moves from the center to the edge of the river channel. As a result, sediment supply in the downstream river will distribute unevenly. Under the erosion of fluid flow, the proportion of fine particles increases, while the proportion of coarse particles decreases gradually in the sediment deposition. The build-up of accumulated sediment mass will cause a significant increase in water level in the river channel, thus creating serious flooding hazard in mountainous rivers.

ACS Style

Ming Lei; Ze-Xing Xu; Tao Zhao; Xie-Kang Wang. Dynamics of loose granular flow and its subsequent deposition in a narrow mountainous river. Journal of Mountain Science 2019, 16, 1367 -1380.

AMA Style

Ming Lei, Ze-Xing Xu, Tao Zhao, Xie-Kang Wang. Dynamics of loose granular flow and its subsequent deposition in a narrow mountainous river. Journal of Mountain Science. 2019; 16 (6):1367-1380.

Chicago/Turabian Style

Ming Lei; Ze-Xing Xu; Tao Zhao; Xie-Kang Wang. 2019. "Dynamics of loose granular flow and its subsequent deposition in a narrow mountainous river." Journal of Mountain Science 16, no. 6: 1367-1380.

Case report
Published: 18 January 2019 in Water
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On 8 August 2017, a runoff-generated debris flow occurred in the Puge County, Sichuan Province of southwestern China and caused huge property damage and casualties (25 people died and 5 people were injured). Emergency field investigations found that paddy fields, dry land, residential buildings and roads suffered different degrees of impact from the debris flow. This paper reveals the formation process of the debris flow by analyzing the characteristics of rainfall precipitation and sediment supply conditions in the study area and it approaches the practical application of hazard prevention and mitigation constructions. Doppler weather radar analysis indicates that a very high intensity rainfall occurred in the middle and upper zones of the basin, illustrating the importance of enhancing rainfall monitoring in high-altitude areas. The abundant supply of deposits in gully channels is among the significant causes of a transformation from mountain floods to large-scale debris flows. It was also found that the two culverts played an important role in the movement affecting the processes of debris flows which has substantially aggravated the destructive outcome. The excessive supply of solid material and local blockage with outburst along a gully must receive significant attention for the prediction of future debris flows, hazard prevention and mitigation measures.

ACS Style

Ming-Liang Chen; Xing-Nian Liu; Xie-Kang Wang; Tao Zhao; Jia-Wen Zhou. Contribution of Excessive Supply of Solid Material to a Runoff-Generated Debris Flow during Its Routing Along a Gully and Its Impact on the Downstream Village with Blockage Effects. Water 2019, 11, 169 .

AMA Style

Ming-Liang Chen, Xing-Nian Liu, Xie-Kang Wang, Tao Zhao, Jia-Wen Zhou. Contribution of Excessive Supply of Solid Material to a Runoff-Generated Debris Flow during Its Routing Along a Gully and Its Impact on the Downstream Village with Blockage Effects. Water. 2019; 11 (1):169.

Chicago/Turabian Style

Ming-Liang Chen; Xing-Nian Liu; Xie-Kang Wang; Tao Zhao; Jia-Wen Zhou. 2019. "Contribution of Excessive Supply of Solid Material to a Runoff-Generated Debris Flow during Its Routing Along a Gully and Its Impact on the Downstream Village with Blockage Effects." Water 11, no. 1: 169.

Article
Published: 16 November 2018 in Journal of Mountain Science
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The influence of vegetation and sediment on flow characteristics in open channels cannot be neglected. To study the flow variability under the effects of the instream natural vegetation and sediment supply, experiments were conducted with varied water and sediment supply in a movable bed of a river prototype. The instantaneous three-dimensional velocities near two types of vegetation patches (the shrub and the weed) and along the centerline of the main channel with vegetation belts were measured using a 3-D side-looking acoustic Doppler velocimetry. The experimental results show that both the instream vegetation and sediment supply strongly affect the flow and turbulence characteristics. In the case of vegetation patches, both the shrub and weed have a considerable influence on the distribution of the streamwise velocity and turbulence intensity of their surrounding water. The streamwise velocity distribution followed as J-shape and linear shape around the weed and shrub under different experimental conditions. The turbulence intensity was large at the top of the weed and shrub; the shrub had its greatest influence on the downstream water flow. In the case of vegetation belts, the streamwise velocity along the centerline of the main channel exhibited an S-shape, J-shape and linear shape at different locations under varied water, vegetation structures and riverbed configurations. The turbulence intensity along the centerline of the main channel ranged from 0.0 to 0.1. The upstream turbulence intensity was affected considerably by a sediment supply, while the downstream turbulence intensity changed with the varied vegetation characteristics and riverbed topography. The second flow coefficient M-value increased longitudinally and was almost positive along the centerline of the main channel, implying that the rotational direction of the secondary current cell was clockwise.

ACS Style

Hai-Zhou Wang; Ze-Xing Xu; Hai-Ti Yu; Xie-Kang Wang. Flow variability along a vegetated natural stream under various sediment transport rates. Journal of Mountain Science 2018, 15, 2347 -2364.

AMA Style

Hai-Zhou Wang, Ze-Xing Xu, Hai-Ti Yu, Xie-Kang Wang. Flow variability along a vegetated natural stream under various sediment transport rates. Journal of Mountain Science. 2018; 15 (11):2347-2364.

Chicago/Turabian Style

Hai-Zhou Wang; Ze-Xing Xu; Hai-Ti Yu; Xie-Kang Wang. 2018. "Flow variability along a vegetated natural stream under various sediment transport rates." Journal of Mountain Science 15, no. 11: 2347-2364.

Journal article
Published: 01 January 2018 in Geomatics, Natural Hazards and Risk
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ACS Style

Bin-Rui Gan; Xing-Nian Liu; Xing-Guo Yang; Xie-Kang Wang; Jia-Wen Zhou. The impact of human activities on the occurrence of mountain flood hazards: lessons from the 17 August 2015 flash flood/debris flow event in Xuyong County, south-western China. Geomatics, Natural Hazards and Risk 2018, 9, 816 -840.

AMA Style

Bin-Rui Gan, Xing-Nian Liu, Xing-Guo Yang, Xie-Kang Wang, Jia-Wen Zhou. The impact of human activities on the occurrence of mountain flood hazards: lessons from the 17 August 2015 flash flood/debris flow event in Xuyong County, south-western China. Geomatics, Natural Hazards and Risk. 2018; 9 (1):816-840.

Chicago/Turabian Style

Bin-Rui Gan; Xing-Nian Liu; Xing-Guo Yang; Xie-Kang Wang; Jia-Wen Zhou. 2018. "The impact of human activities on the occurrence of mountain flood hazards: lessons from the 17 August 2015 flash flood/debris flow event in Xuyong County, south-western China." Geomatics, Natural Hazards and Risk 9, no. 1: 816-840.

Journal article
Published: 01 October 2017 in Journal of Hydrologic Engineering
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Nappe flow applies to small discharges, and investigation of nappe flow surges helps to understand the mechanism of water flow in stepped open channels. The objective of this paper is to investigate the nappe flow surge propagation down stepped open channels. First, an analytical solution of dam-break shock waves or flood waves is derived. Then, the theoretical solution is used to calculate the wavefront and celerity and is verified using experiments on surging waters down a stepped slope in a 20-m-long and 0.5-m-wide open channel under three conditions: one for smooth bed surface and the others for rough bed surface glued with uniform sediment (of diameter ds=1.715 mm and ds=3.5 mm). For calculating the wavefront propagation in a stepped open channel, a formula for resistance, composed of grain resistance and step geometry resistance, is developed. Unlike skimming flow, the roughness of step surface in the nappe flow regime influences the friction factor fs. Results show that the friction factor increases with the relative roughness height (ds/d0). The theoretical solution for the wavefront location and celerity is then revised by combining the friction formula, and the revised solution is tested for a wide range of experimental data. Test results show that the revised solution fits the measured data quite well. Comparing with the solution previously derived, the revised solution derived in this study more accurately predicts the wavefront location and celerity for the nappe flow condition.

ACS Style

Fengguang Yang; Vijay P. Singh; Xiekang Wang; Xingnian Liu. Nappe Flow Surges down a Rough-Stepped Sloping Channel. Journal of Hydrologic Engineering 2017, 22, 04017044 .

AMA Style

Fengguang Yang, Vijay P. Singh, Xiekang Wang, Xingnian Liu. Nappe Flow Surges down a Rough-Stepped Sloping Channel. Journal of Hydrologic Engineering. 2017; 22 (10):04017044.

Chicago/Turabian Style

Fengguang Yang; Vijay P. Singh; Xiekang Wang; Xingnian Liu. 2017. "Nappe Flow Surges down a Rough-Stepped Sloping Channel." Journal of Hydrologic Engineering 22, no. 10: 04017044.

Article
Published: 07 September 2017 in Journal of Mountain Science
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Particle Image Velocimetry (PIV) technique was used to test the analogues of hyper-concentrated flow and dilute debris flow in an open flume. Flow fields, velocity profiles and turbulent parameters were obtained under different conditions. Results show that the flow regime depends on coarse grain concentration. Slurry with high fine grain concentration but lacking of coarse grains behaves as a laminar flow. Dilute debris flows containing coarse grains are generally turbulent flows. Streamlines are parallel and velocity values are large in laminar flows. However, in turbulent flows the velocity diminishes in line with the intense mixing of liquid and eddies occurring. The velocity profiles of laminar flow accord with the parabolic distribution law. When the flow is in a transitional regime, velocity profiles deviate slightly from the parabolic law. Turbulent flow has an approximately uniform distribution of velocity and turbulent kinetic energy. The ratio of turbulent kinetic energy to the kinetic energy of time-averaged flow is the internal cause determining the flow regime: laminar flow (k̅/K̅ < 0.1); transitional flow (0.1 < k̅/K̅ < 1); and turbulent flow (k̅/K̅ > 1). Turbulent kinetic energy firstly increases with increasing coarse grain concentration and then decreases owing to the suppression of turbulence by the high concentration of coarse grains. This variation is also influenced by coarse grain size and channel slope. The results contribute to the modeling of debris flow and hyper-concentrated flow.

ACS Style

Yan Liu; Hui-Feng Wang; Hua-Yong Chen; Kai-Heng Hu; Xie-Kang Wang. The properties of dilute debris flow and hyper-concentrated flow in different flow regimes in open channels. Journal of Mountain Science 2017, 14, 1728 -1738.

AMA Style

Yan Liu, Hui-Feng Wang, Hua-Yong Chen, Kai-Heng Hu, Xie-Kang Wang. The properties of dilute debris flow and hyper-concentrated flow in different flow regimes in open channels. Journal of Mountain Science. 2017; 14 (9):1728-1738.

Chicago/Turabian Style

Yan Liu; Hui-Feng Wang; Hua-Yong Chen; Kai-Heng Hu; Xie-Kang Wang. 2017. "The properties of dilute debris flow and hyper-concentrated flow in different flow regimes in open channels." Journal of Mountain Science 14, no. 9: 1728-1738.

Research papers
Published: 07 June 2017 in Journal of Hydraulic Research
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Channel topography plays an important role in debris flow entrainment processes. Field observations and flume experiments have demonstrated two notable erosion effects: abrasion on convex slopes resulting from layer-by-layer shearing and impact erosion on concave slopes. Most existing formulas for debris flow entrainment rates are derived from the uniform slope assumption and do not account for the two erosion effects. In order to take abrasion and impact erosion into consideration, this study incorporated two channel curvature functions into the entrainment formula that is based on equilibrium between flow frictional forces and basal resistance forces. The two functions control the effects of entrainment on different slope types and are based on empirical relationships with curvature obtained in flume experiments. The revised formula provides a unified procedure for debris flow entrainment rates in non-uniform channels.

ACS Style

Pu Li; Kaiheng Hu; Xiekang Wang. Debris flow entrainment rates in non-uniform channels with convex and concave slopes. Journal of Hydraulic Research 2017, 56, 156 -167.

AMA Style

Pu Li, Kaiheng Hu, Xiekang Wang. Debris flow entrainment rates in non-uniform channels with convex and concave slopes. Journal of Hydraulic Research. 2017; 56 (2):156-167.

Chicago/Turabian Style

Pu Li; Kaiheng Hu; Xiekang Wang. 2017. "Debris flow entrainment rates in non-uniform channels with convex and concave slopes." Journal of Hydraulic Research 56, no. 2: 156-167.

Preprint
Published: 19 October 2016
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An accurate assessment of the stage-discharge relationship in open channel flows is necessary and important to the design and management of hydraulic structures and engineering in practical hydrosystems such as rivers and streams. While the flow structures and patterns at open channel junctions are interesting and have been widely studied in the literature, this paper focuses further on the effect of flow junctions on stage-discharge relationship at mountain river confluences. In this study, both the flume and physical model experiments are designed and performed carefully to test and analyze the complex flow structures and characteristics at river confluences with different configurations and hydraulic conditions. The impacts of the flow junctions on the traditional stage-discharge relationship are analyzed in this study. The results of this study are discussed in the paper for the understanding of flow structures at flow junctions and the design and management of hydraulic structures in river engineering.

ACS Style

Xiekang Wang; Haizhou Wang; Xufeng Yan; Xingnian Liu; Huan-Feng Duan. Experimental Study on the Hydrodynamic Influence of River Flow Confluences to the Open Channel Stage-Discharge Relationship. 2016, 1 .

AMA Style

Xiekang Wang, Haizhou Wang, Xufeng Yan, Xingnian Liu, Huan-Feng Duan. Experimental Study on the Hydrodynamic Influence of River Flow Confluences to the Open Channel Stage-Discharge Relationship. . 2016; ():1.

Chicago/Turabian Style

Xiekang Wang; Haizhou Wang; Xufeng Yan; Xingnian Liu; Huan-Feng Duan. 2016. "Experimental Study on the Hydrodynamic Influence of River Flow Confluences to the Open Channel Stage-Discharge Relationship." , no. : 1.

Journal article
Published: 10 February 2016 in Journal of Mountain Science
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The rapid changes in flow pattern due to varying channel widths will make significantly impact on the hydraulic structures and evolutions of open channel. To better understand the impact of varying width, a flume experiment with adjustable width and a depth-averaged two-dimension numerical model were used to analyze the variations of flow parameters. Our experimental results showed that flow velocity gradually increased with decreasing water depth in converging region, and decreased with increasing water depth in diverging zones. It was also found that the turbulence intensity laws in three directions were not agreed with the theoretical relationships proposed by Nezu and Nakagawa in 1993 in straight open channel flows. The flow in the channel with varying width may change from the supercritical flow to the subcritical flow as a function of Froude number. Our numerical simulations with different flow rates showed that most of the hydraulic jumps in diverging region were submerged jump and the degree of submergence increased with increasing flow rate in gradual channel transition. When the flow rate increased, the range of supercritical flow rapidly decreased and the flow changed from the supercritical condition to the subcritical condition in diverging sections.

ACS Style

Xie-Kang Wang; Bing-Jie Wang; Xing-Nian Liu; Li-Qiong Zhang. Effects of river width changes on flow characteristics based on flume experiment. Journal of Mountain Science 2016, 13, 361 -368.

AMA Style

Xie-Kang Wang, Bing-Jie Wang, Xing-Nian Liu, Li-Qiong Zhang. Effects of river width changes on flow characteristics based on flume experiment. Journal of Mountain Science. 2016; 13 (2):361-368.

Chicago/Turabian Style

Xie-Kang Wang; Bing-Jie Wang; Xing-Nian Liu; Li-Qiong Zhang. 2016. "Effects of river width changes on flow characteristics based on flume experiment." Journal of Mountain Science 13, no. 2: 361-368.

Journal article
Published: 25 July 2015 in Journal of Mountain Science
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Roughness elements are various in a mountain area; they include gravel and ground surface vegetation that often result in surface friction drag to resist overland flows. The variation and characteristics of flow resistance strongly impact the overland flow process and watershed floods. In view of the universal existence of natural vegetation, such as Chlorophytum malayense (CM) or Ophiopogon bodinieri (OB), and the sand-gravel bed of the river channel, it is important to understand the role of different types of roughness elements in flow resistance. This study was performed to investigate and compare through flume experiments the behaviors of overland flow resistance by the reaction of multi-scale configuration of different roughness elements. The result showed that the resistance coefficient gradually reduced versus the increase of flow rate in unit width and tended to be a constant when q = 3.0X10-3 m2/s, Fr = 1.0, and Re = 4000 for slopes of 6 to 10 degrees. The gap of the vegetated rough bed and the gravel rough bed is limited to the same as the gap of the two types of vegetation, CM and OB. It was noted that the vegetation contributed to the increase in form resistance negatively and may lead to the mean resistance on decrease. To classify the flow pattern, the laminar flows were described by Darcy-Weisbach's equation. In the study the f-Re equation of vegetated bed was developed with Received: 21 January 2015 Accepted: 10 April 2015 f = 5000/Re. The friction coefficient for laminar flows can be regarded as the critical value for identifying the transformation point of the flow pattern.

ACS Style

Chen Ye; Xing-Nian Liu; Xie-Kang Wang. Effects of roughness elements distribution on overland flow resistance. Journal of Mountain Science 2015, 12, 1145 -1156.

AMA Style

Chen Ye, Xing-Nian Liu, Xie-Kang Wang. Effects of roughness elements distribution on overland flow resistance. Journal of Mountain Science. 2015; 12 (5):1145-1156.

Chicago/Turabian Style

Chen Ye; Xing-Nian Liu; Xie-Kang Wang. 2015. "Effects of roughness elements distribution on overland flow resistance." Journal of Mountain Science 12, no. 5: 1145-1156.

Journal article
Published: 01 June 2015 in Journal of Hydrodynamics
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ACS Style

Xie-Kang Wang; Zi-Jing Yi; Xu-Feng Yan; Er Huang; Xing-Nian Liu. Experimental study of the flow structure of decelerating and accelerating flows under a gradually varying flume. Journal of Hydrodynamics 2015, 27, 340 -349.

AMA Style

Xie-Kang Wang, Zi-Jing Yi, Xu-Feng Yan, Er Huang, Xing-Nian Liu. Experimental study of the flow structure of decelerating and accelerating flows under a gradually varying flume. Journal of Hydrodynamics. 2015; 27 (3):340-349.

Chicago/Turabian Style

Xie-Kang Wang; Zi-Jing Yi; Xu-Feng Yan; Er Huang; Xing-Nian Liu. 2015. "Experimental study of the flow structure of decelerating and accelerating flows under a gradually varying flume." Journal of Hydrodynamics 27, no. 3: 340-349.

Journal article
Published: 27 March 2015 in KSCE Journal of Civil Engineering
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The flow structures and bed formation have been analyzed at typical cross-sections in flat-rigid and inclined beds with small width-to-depth ratio through the observational data in a U-shape bend flume. The results show that the bed configuration strongly affects the variations of the super-elevation of water surface and the intensity of secondary flow. The trend for the intensity of secondary flow shows an increase in the first part of the bend until a maximum value at 60° to the bend, and then decreases in the second part of the bend on flat rigid bed. The analyses also indicate that the water level trend between the outer bank and inner bank inversely varies at the bend entrance and exit in comparison with that on a rigid bed. The intensity of secondary flow shows two peaks of variation exist at sections 60° and 165°, which are associated with the peaks of transverse bed slope on inclined bed. In addition, the maximum deposition in the inner bank and scour in the outer bank associated with the maximum finer and coarsening of bed material occurs at section 60° and 165° related to two peaks of the intensity of secondary flow.

ACS Style

Xiekang Wang; Xingnian Liu; Wang Xiekang; Liu Xingnian. Experimental investigation of flow structures and bed deformation with small width-to-depth ratio in a bend flume. KSCE Journal of Civil Engineering 2015, 20, 497 -508.

AMA Style

Xiekang Wang, Xingnian Liu, Wang Xiekang, Liu Xingnian. Experimental investigation of flow structures and bed deformation with small width-to-depth ratio in a bend flume. KSCE Journal of Civil Engineering. 2015; 20 (1):497-508.

Chicago/Turabian Style

Xiekang Wang; Xingnian Liu; Wang Xiekang; Liu Xingnian. 2015. "Experimental investigation of flow structures and bed deformation with small width-to-depth ratio in a bend flume." KSCE Journal of Civil Engineering 20, no. 1: 497-508.

Journal article
Published: 01 February 2014 in Journal of Hydrodynamics
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ACS Style

Xie-Kang Wang; Xu-Feng Yan; Su-Fen Zhou; Er Huang; Xing-Nian Liu. Longitudinal variations of hydraulic characteristics of overland flow with different roughness. Journal of Hydrodynamics 2014, 26, 66 -74.

AMA Style

Xie-Kang Wang, Xu-Feng Yan, Su-Fen Zhou, Er Huang, Xing-Nian Liu. Longitudinal variations of hydraulic characteristics of overland flow with different roughness. Journal of Hydrodynamics. 2014; 26 (1):66-74.

Chicago/Turabian Style

Xie-Kang Wang; Xu-Feng Yan; Su-Fen Zhou; Er Huang; Xing-Nian Liu. 2014. "Longitudinal variations of hydraulic characteristics of overland flow with different roughness." Journal of Hydrodynamics 26, no. 1: 66-74.