نتایج جستجو برای: bank scour

تعداد نتایج: 65121  

2006

stable pile depth in the Snowy River study (SKM 2005) is outlined. The inputs used in the run of the LLP99 model were: • single soil layer, • very high flexural stiffness of pile (1,000,000 kN/m). • pile width = 0.3 m (i.e. wooden pile), • shear strength in the absence of lateral stress (for unconsolidated sand 150 kN/m was used), • effective unit weight of soil (15 kN/m), • active lateral effe...

Journal: :journal of water sciences research 2011
t esmaeili a.a dehghani m.r pirestani tetsuya sumi

local scouring around bridge piers is a natural phenomenon caused by the erosive process of flowing stream on alluvial beds. the 3d flow field around bridge piers interacting with the bed materials increases complexity of local scour process. the local scour depth develops in accelerated flows and if it is not predicted correctly, the bottom level of local scour hole will exceed the original le...

Journal: :Journal of Hydrology and Hydromechanics 2021

Abstract Large debris transported by flood affects scour features at bridge piers and increases the risks of structural failure. Geometric characteristics relative position pier with respect to river bank are important parameters for process. The interaction between water flow accumulation shear stress, turbulence consequently enhances depth pier. This paper aims analyzing such effects on evolu...

2017
Fei Fan Bingchen Liang Yaru Li Yuchuan Bai Yanjun Zhu Zhixia Zhu

Rigid-lid approximation is usually used to replace the free surface in scour simulation. The influence of the rigid lid assumption on the prediction precision of scour hole in steady flow is studied in this paper. Firstly, a local scour model was constructed based on the open sources Computational Fluid Dynamics (CFD) model OpenFOAM, where both the bed load and suspended load were considered. I...

Journal: :Earth Science Informatics 2015
Mohammad Najafzadeh Siow Yong Lim

An improved neuro-fuzzy based group method of data handling using the particle swarm optimization (NF-GMDH-PSO) is developed as an adaptive learning network to predict the localized scour downstream of a sluice gate with an apron. The input characteristic parameters affecting the scour depth are the sediment size and its gradation, apron length, sluice gate opening, and the flow conditions upst...

2009
B. D. ADHIKARY

Simulation of scour-pit formations under the bridge decks and around the bridge piers, due to sediment suspension and transport caused by flooding and pressure flow conditions, is of significant interest nowadays to computational fluid dynamics (CFD) and hydraulic researchers. From CFD perspective, analysis of bridge under various flooding conditions and impact of the drag and lift forces on it...

2012
M. Habibi

The "vertical drop Structure" is one of the basic types used in channel system flow. Drops are used as slope breakers in some parts of channels where we encounter supercritical slopes. Scour is a dynamic phenomenon that is visible in vertical drop tail water depth. Because of complexity of Scour process and simultaneous testing of variables’ effective compliance, studies are still underway to d...

Journal: :مهندسی عمران فردوسی 0
حسین خزیمه نژاد مهدی قمشی یوسف رمضانی

scour around bridge piers is one of the most important fields of hydraulic research. local scour around bridge piers and abutment is one of the main reasons of bridge failures. in the field of scour at the bridges, researches are more focus on scour of piers in compare with abutment. while the available information on the bridge failures required cost, the major problems are related to abutment...

2007
A. G. Davies J. M. Brown

Field observations and model simulations are presented of the tidal flow over a scour hole at the mouth of the Dyfi Estuary, mid-Wales, U.K. This scour hole is maintained by locally high flow speeds resulting from convergence, and then divergence, of the flow over the hole. Fixed features of the local bathymetry may also have served to stabilise its location (over decades). Model simulations of...

2005
EDWARD A. KELLER

Stream channel development in forested areas is profoundly influenced by large organic debris (logs , limbs and rootwads greater than 10 cm in diameter) in the channels. In low gradient meandering streams large organic debris enters the channel through bank erosion , mass wasting, blowdown, and collapse of trees due to ice loading. In small streams large organic debris may locally influence cha...

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