PIV MEASUREMENTS AROUND A SUBMERGED CYLINDER WITH LOCAL SCOUR PROTECTION

2019 ◽  
Author(s):  
PRISCILLA WILLIAMS ◽  
RAM BALACHANDAR ◽  
VESSELINA ROUSSINOVA ◽  
RONALD BARRON
Keyword(s):  
Local Scour ◽  
Piv Measurements ◽  
Submerged Cylinder ◽  
Scour Protection

scholarly journals Enhancing scour protection in river bends: a novel slotted bank-attached vane

2020 ◽  
Vol 20 (6) ◽  
pp. 2175-2184
Author(s):  
Mohamad Azizipour ◽  
Farshid Amirsalari Meymani ◽  
Mohammad Mahmoodian Shooshtari
Keyword(s):  
Effective Area ◽  
Local Scour ◽  
Flume Experiments ◽  
Rectangular Slot ◽  
Outer Bank ◽  
Scour Hole ◽  
Submerged Vane ◽  
River Bends ◽  
Scour Protection ◽  
Control Erosion

Abstract One of the most effective approaches for bank control erosion is using bank-attached vanes. In spite of the superiority of the bank-attached vanes to spur dikes, the vanes' tips are still vulnerable to local scour caused by flow–structure interaction. In this study, slotted bank-attached vanes are proposed to reduce local scour at the tip of the triangular submerged vane. For this, a rectangular slot is created parallel to the chord of the vane with an area of ten percent of the effective area of the vane surface. Two types of conventional vanes and slotted vanes were installed at different angles of attack of 23, 30, 40 and 60 degrees in an arch flume. Experiments were carried out in clear water conditions with different flow regimes with Froude numbers of Fr = 0.287, 0.304 and 0.322. The results show that the slotted vane outperforms the conventional vane by reducing maximum scour depth by about 70, 20, 17 and 54 percent for different angles of attack of 23, 30, 40 and 60 degrees, respectively. The proposed slotted vane also resulted in reduction of scour hole volume around the vane and formed the scour hole away from the outer bank.

scholarly journals Experimental Investigation of Local Scour Protection for Cylindrical Bridge Piers Using Anti-Scour Collars

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1515 ◽  
Author(s):  
Shunyi Wang ◽  
Kai Wei ◽  
Zhonghui Shen ◽  
Qiqi Xiang
Keyword(s):  
Protective Effect ◽  
Local Scour ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Experimental Program ◽  
Design Parameters ◽  
External Diameter ◽  
River Sand ◽  
Bed Scour ◽  
Scour Protection

Local scour of bridge piers is one of the main threats responsible for bridge damage. Adopting scour countermeasures to protect bridge foundations from scour has become an important issue for the design and maintenance of bridges located in erodible sediment beds. This paper focuses on the protective effect of one active countermeasure named an “anti-scour collar” on local scour around the commonly used cylindrical bridge pier. A cylindrical pier model was set up in a current flume. River sand with a median particle size of 0.324 mm was selected and used as the sediment in the basin. A live-bed scour experimental program was carried out to study the protective effect of an anti-scour collar by comparing the local scour at a cylindrical bridge pier model with and without collar. The effects of three design parameters including collar installation height, collar external diameter and collar protection range, on the scour depth and scour development were investigated parametrically. According to the experimental results, it can be concluded that: the application of an anti-scour collar alleviates the local scour at the pier effectively; and the protection effect decreases with an increase in the collar installation height, but increases with an increase in the collar external diameter and the protection range. Design suggestions for improving the scour protective effect of the anti-scour collar are summarized and of great practical guiding significance to the development of anti-scour collars for bridge piers.

scholarly journals Local scour protection using geocell for downstream of spillway

2021 ◽  
Vol 9 (3B) ◽  
Author(s):  
Enes GUL ◽  
◽  
Talha SARICI ◽  
Omerul Faruk DURSUN ◽  
◽  
...  
Keyword(s):  
Local Scour ◽  
Hydraulic Structures ◽  
Scour Depth ◽  
Percentage Reduction ◽  
Confinement System ◽  
Bed Materials ◽  
Scour Protection

Local scour is an important problem for hydraulic structures. The local scour in the downstream of dams causes problems such as the damage of the dam body stabilization, erosion of the slopes, and the submergence of the turbines. There are many studies investigating the local scour prediction of the downstream of the hydraulic structures, but in recent years, these studies have been replaced by studies of local scour reduction. The new idea of confining the bed materials using the geocell is becoming a popular solution. This solution can be especially used for the reinforcement of the soils. In this study, the preventability of the local scour downstream of chute channel by cellular confinement system, also known as geocell, was investigated. As a result, in case of using geocell, percentage reduction of the maximum scour depth up to 40.63% was observed.

scholarly journals Scour Protection of Underwater Pipelines

2018 ◽  
Vol 7 (4) ◽  
pp. 171
Author(s):  
Liquan Xie ◽  
Yehui Zhu
Keyword(s):  
Literature Review ◽  
Numerical Simulations ◽  
Local Scour ◽  
The Self ◽  
Research Progress ◽  
Submarine Pipeline ◽  
Practical Engineering ◽  
Scour Protection ◽  
Engineering Projects

 A detailed literature review on the protection of local scour beneath a submarine pipeline is presented. The review covers two basic parts of countermeasures against the pipeline scour, namely preventing the onset of scour and stimulating the self-burial of a pipeline. The research progress on the methods of the two sections is discussed in detail separately. The methods preventing the onset of scour have been extensively studied, but the understanding on their mechanisms is yet to be improved. The progress in stimulating the self-burial of a pipeline mainly focuses on a spoiler attached to a pipeline, which is investigated comprehensively with both experiments and numerical simulations. Both parts of countermeasures have been applied in some practical engineering projects and the protection effects are generally satisfying.

Scour problems at railway bridges on the Thompson River, B.C.

1980 ◽  
Vol 7 (2) ◽  
pp. 357-372 ◽  
Author(s):  
Charles R. Neill ◽  
L. Ralph Morris
Keyword(s):  
British Columbia ◽  
Thin Layer ◽  
Special Form ◽  
Local Scour ◽  
Main Line ◽  
Railway Bridges ◽  
Model Study ◽  
History Of ◽  
Scour Protection ◽  
Research And Design

The paper describes the history of riverbed changes and associated pier foundation problems at a series of five bridges along the Canadian National main line in the Thompson River valley of British Columbia. Pier failures were experienced in past years at two of these bridges, and there is a long history of placing rock riprap to combat local scour. The riverbed consists mainly of a thin layer of coarse alluvium overlying consolidated silt and clay.Special investigations conducted for one bridge, including a hydraulic model study, are described in some detail, and various schemes considered for foundation upgrading are outlined. Details are given of a special form of scour protection apron that was installed at one pier.Some research and design implications of the cases described are discussed briefly.

Local Scour and Protection of F3 Offshore GBS Platform

2002 ◽  
Author(s):  
Klaas Jan Bos ◽  
Zhiwen Chen ◽  
Henk J. Verheij ◽  
Martijn Onderwater ◽  
Mees Visser
Keyword(s):  
Cost Effective ◽  
Model Tests ◽  
Local Scour ◽  
Protection System ◽  
Small Scale ◽  
Field Observations ◽  
Empirical Formulas ◽  
The North ◽  
Survey Strategy ◽  
Scour Protection

In 1992 a GBS (Gravity Based Structure) was placed in the F3 block in the Dutch sector of the North Sea. Gabion mattresses around the GBS were applied to prevent scour. The potential scour and the required dimensions of the gabion mattresses were determined before the installation in small-scale physical model tests. After the installation of the GBS, annual surveys have been carried out to provide information about the scour development around the GBS and the status of the protection system. This paper presents field observations of local scour development around the F3 GBS platform and an evaluation of the performance of the scour protection system. The objectives were to assess the maximum scour around the GBS and to determine a cost-effective survey strategy. To assess the maximum scour around the GBS, metocean conditions for the F3 GBS location were hindcasted for the period between the platform installation and the latest survey. The observed scour depths were analysed and compared with predictions both from the model tests and from existing empirical formulas. The results showed that the predicted scour depths based on the model tests agree reasonably well with the field observations. The empirical formulas give larger scour depths than the surveys. Based on the field observations in combination with predictions of the models, the maximum scour depths under the design extreme environmental conditions have been determined. To determine a cost effective survey strategy, the behaviour and performance of the gabion mattresses were evaluated based on the annual surveys and video inspections. It was concluded that the protection system has functioned well and no damage was observed. On the basis of the maximum expected scour and the performance of the gabion mattresses, it was considered that the survey frequency may be reduced. Surveys and inspections may be carried out every three years instead of every year, and after a severe storm.

scholarly journals Scour Protection Effects of a Geotextile Mattress with Floating Plate on a Pipeline

2020 ◽  
Vol 12 (8) ◽  
pp. 3482
Author(s):  
Yehui Zhu ◽  
Liquan Xie ◽  
Tsung-Chow Su
Keyword(s):  
Hydraulic Gradient ◽  
Local Scour ◽  
Test Results ◽  
Plate Height ◽  
Floating Plate ◽  
Oil Transportation ◽  
Parametric Effects ◽  
Opening Ratio ◽  
Series Of Experiments ◽  
Scour Protection

Underwater pipelines are vital to the oil industry. Extending the service life of these pipelines is a key issue in improving the sustainability of oil transportation. A geotextile mattress with floating plate (GMFP) is a novel and sustainable countermeasure for scour and erosion control and is herein introduced to protect a partially buried pipeline from local scour in steady currents. A series of experiments was designed to verify the protection capabilities of the GMFP and investigate its parametric effects on protection. The average seepage hydraulic gradient under the pipeline was adopted to depict the protection effects of the GMFP, and was calculated with the pore pressure readings under the pipeline. The test results show that the GMFP is capable of protecting a pipeline from the onset of local scour in a unidirectional current. The average seepage hydraulic gradient below the pipeline decreases remarkably after a GMFP is installed. The average hydraulic gradient shows a descending trend with increased sloping angle α when 0.64 < sinα < 0.77. The hydraulic gradient hits a nadir at sinα = 0.77 and climbs with the increasing sloping angle when sinα > 0.82. The hydraulic gradient ascends when the bottom opening ratio δ increases from 0.167 to 0.231, due to the decreased intensity of the bottom vortex. The hydraulic gradient drops with a rising plate height, except for a fluctuation at Hp = 0.12 m. An approximate negative correlation is found between the obstruction height of the floating plate and the average hydraulic gradient under the pipeline. This could be partially attributed to the extension and amplification of the bottom vortex on the leeside of the pipeline due to the increased plate obstruction height.

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