نتایج جستجو برای: local scour

تعداد نتایج: 533069  

2012
Marcelo H. García Xiaofeng Liu Salih Demir

The main objective of this effort has been the direct observation and monitoring of the burial process of finite-length cylinders (model mines) induced by the combined action of waves, currents and pure oscillatory flows. The experimental conditions have made it possible to observe the burial process due to both local scour around the mines as well as the passage of large sandwaves. These rathe...

2014
S. Howard A. Etemad-Shahidi

Pile scour may cause instability to the structures they support. Ensuring a safe and economically sound design is essential for the wider community. Although much laboratory research has been carried out on scour at pile groups, there are still significant gaps in prediction formulae. This study has been conducted to develop a formula for scour at pile arrangements of non-uniform spacing. The s...

2009
Abdel-Azim M. Negm

Scour downstream (DS) of hydraulic structures (HS) may endanger the safety of the structures if the necessary precuations are not considered during the design stage. Normally, different measures produce different effects on reducing the maximum scour depth DS of HS. One of the important HSs is the abruptly enlarged (or sudden expanding) stilling basins. In this paper, the effects of different a...

2016
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...

ژورنال: علوم آب و خاک 2009
حیدرپور, منوچهر, موسوی, فرهاد , کیخایی, ملیحه,

Ripraps are placed around bridge piers to prevent scour and secure the piers from failure. Proper riprap cover is essential to be economical. The present study examines using of riprap for reduction of local scour in piers group and the results are compared with data from riprap on a single pier. The models consist of two and three circular-shaped piers in line with the flow, with the diameter ...

In this research a physical model is presented. A trapezoidal shape of channel with 1.45 m width, 1 meter depth and banks slope of 1H: 1.5V was used. Circular piers (6, 8 and 10cm diameter) were tested under three different flow discharges of 50, 65 and 80 lit/s and three different median bed material sizes equal to 0.94, 1.31 and 2.12 mm. Seven different longitude distance to pier diameter rat...

2004
A. R. Kambekar M. C. Deo

The interaction between ocean environment and pile structure is so complex that despite considerable laboratory as well as prototype studies estimation of scour depth and its geometry in a generalized and accurate form are still difficult to make. One of the reasons underlying this uncertainty could be the limitation of the statistical curve fitting technique, commonly employed to analyse the c...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2015
C Baykal B M Sumer D R Fuhrman N G Jacobsen J Fredsøe

Flow and scour around a vertical cylinder exposed to current are investigated by using a three-dimensional numerical model based on incompressible Reynolds-averaged Navier-Stokes equations. The model incorporates (i) k-ω turbulence closure, (ii) vortex-shedding processes, (iii) sediment transport (both bed and suspended load), as well as (iv) bed morphology. The influence of vortex shedding and...

2014
Gaël Epely-Chauvin Giovanni De Cesare Sebastian Schwindt

Turbulences in liquids caused by jets can be of interest for numerous applications. For one, it concerns flood spillway structures within civil engineering but also is key in any area where turbulent mixing is present. The numerical simulations of jets that impinge into plunge pools are still in an early phase of their development. This paper verifies the accuracy of the Flow-3D software packag...

2010
Mohammad Muzzammil

Mohammad Muzzammil Department of Civil Engineering, AMU, Aligarh, UP 202002, India E-mail: [email protected] An accurate estimation of the maximum possible scour depth at bridge abutments is of paramount importance in decision-making for the safe abutment foundation depth and also for the degree of scour counter-measure to be implemented against excessive scouring. Despite analysis of...

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