Experimental Study on the Effect of Froude Number on Temporal Variation of Scour around a T Shaped Spur Dike in a 90 Degree Bend

2011 ◽  
Vol 147 ◽  
pp. 75-79 ◽  
Author(s):  
Mohammad Vaghefi ◽  
Masoud Ghodsian ◽  
Arash Adib
Keyword(s):  
Experimental Study ◽  
Temporal Variation ◽  
Froude Number ◽  
Average Diameter ◽  
Clear Water ◽  
Spur Dike ◽  
Outer Banks ◽  
The Past ◽  
Scour Hole ◽  
Spur Dikes

In the past few decades, the use of spur dikes for stability of the outer banks of rivers has attracted the attention of hydraulic engineers. Setting spur dikes in the flow’s direction leads to local scour around the spur dike and changes the topography of the bed. This paper deals with the study of the temporal variation of the scour hole and topography of the bed around a T shaped spur dike located in a 90 degree bend. The experiments were carried out in a channel with a 90 degrees bend. Uniform sediments having an average diameter of 1.28mm were used under clear water condition. The effects of Froude number on the amount and the geometry of scour hole around a T shaped spur dike and the time variation of scour were investigated.

scholarly journals Velocity Field and Turbulence Structure around Spur Dikes with Different Angles of Orientation under Ice Covered Flow Conditions

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1844
Author(s):  
Rahim Jafari ◽  
Jueyi Sui
Keyword(s):  
Flow Characteristics ◽  
Ice Cover ◽  
Roughness Coefficient ◽  
Turbulence Structure ◽  
Flow Conditions ◽  
Spur Dike ◽  
Turbulence Structures ◽  
Scour Hole ◽  
Spur Dikes ◽  
Set Up

Spur dikes are well-known structures that are widely used in rivers and coastal regions. Depending on their types, sizes, and orientation angles, spur dikes can substantially change flow characteristics. Results of previous studies indicate that the presence of an ice cover in rivers can cause complicated flow structures. The present experimental study investigates velocity fields and turbulence structures in the vicinity of spur dikes under ice cover with different roughness coefficients. The spur dikes were set up at the following three angles of orientation, 90°, 60°, and 45°. Our results show that the strongest velocity fluctuation occurs immediately above the scour hole surface and very close to the dike tip. The increase in the dike angle toward upstream, the velocity component values increase, leads to a larger scour hole. Results show that an increase in dike angle of each 10° (from 45° to 90°) increases the scour depth between 5% and 10%, depending on flow conditions. Furthermore, the increase in the cover roughness coefficient and the blockage ratio of a spur dike leads to a further increase in turbulence kinetic energy and 3D velocity components values. The findings of this study imply that the appearance of an ice cover can increase turbulence intensities up to nearly 30%.

scholarly journals Bridge Abutment Protection against Scouring for Unsteady Flow Conditions

2021 ◽  
Author(s):  
Maryam Khajavi ◽  
Seyed Mahmood Kashefipour ◽  
Mahmood Shafai Bejestan
Keyword(s):  
Unsteady Flow ◽  
Steady Flow ◽  
Clear Water ◽  
Flow Conditions ◽  
Spur Dike ◽  
Base Time ◽  
Bridge Abutment ◽  
Water Conditions ◽  
Scouring Process ◽  
Spur Dikes

The bridge abutment is one of the main parts of a bridge and significantly contributes to bridge stability. This study experimentally investigated the effect of the unsteadiness characteristics of hydrographs on the scouring phenomenon around the bridge abutment under clear water conditions. The ability of the permeable and impermeable spur dikes and their distances from the abutment at its upstream on the control of scouring around the bridge abutment was also investigated. The experimental observations imply that the effect of unsteady flow on the scouring process is relatively similar to the steady flow conditions. The results showed that the base time of hydrographs, the type of spur dikes, and the distance of spur dikes from the bridge abutment were the dominant parameters among the considered parameters in this study on the scouring process around the abutment. The results also revealed that the impermeable spur dike was able to completely eliminate scouring around the bridge abutment for two distances of 2L and 3L (where L is the abutment length) for both steady and unsteady flow conditions.

scholarly journals The 3-D Morphology Evolution of Spur Dike Scour under Clear-Water Scour Conditions

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1583 ◽  
Author(s):  
Li Zhang ◽  
Hao Wang ◽  
Xianqi Zhang ◽  
Bo Wang ◽  
Jian Chen
Keyword(s):  
Shear Stress ◽  
Morphological Evolution ◽  
Golden Section ◽  
Evolution Process ◽  
Bed Shear Stress ◽  
Clear Water ◽  
Power Functions ◽  
Spur Dike ◽  
Evolution Characteristics ◽  
Scour Hole

By changing the alignment angle of spur dike, this study focused on the evolution of scour hole morphology in three alignments under clear-water scour conditions, including the 3-D structure of the scour hole, 2-D profile morphological evolution process and the evolution characteristics of the local bed shear stress. The results show that the plane area and volume of the scour hole both are power functions over time, which is similar to the evolution characteristics of scour depth. Local scour includes three stages: The initial stage, development stage and balance stage. The local bed shear stress presents successively: τb > τc, τb = τc and τb < τc. Based on this characteristic, the evolution mechanism between scour hole morphology and the local bed shear stress is further clarified. Furthermore, although the alignment of the spur dike significantly affects the longitudinal and vertical dimension erosion rates of the scour hole, the scour hole morphology is not only relatively constant but also has a specific proportion, and the evolution process is orderly in the whole process of evolution. To the scouring equilibrium state, the length of the scour hole on the upstream and downstream of the spur dike is approximately in line with the golden section feature. The related results provide technical support for scour parameter design and scour hole protection of spur dike in flood period.

Spatio-temporal Variation Characteristics of Surface Net Radiation in China over the Past 50 Years

2013 ◽  
Vol 15 (1) ◽  
pp. 1 ◽  
Author(s):  
Yangzi GAO ◽  
Honglin HE ◽  
Li ZHANG ◽  
Qianqian LU ◽  
Guirui YU ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Net Radiation ◽  
The Past ◽  
Variation Characteristics ◽  
Spatio Temporal

The Clogging Behavior of a Vortex Pump: An Experimental Study on the Influence of Impeller Designs

2017 ◽  
Author(s):  
Angela Gerlach ◽  
Dorian Perlitz ◽  
Flemming Lykholt-Ustrup ◽  
Christian Brix Jacobsen ◽  
Paul Uwe Thamsen
Keyword(s):  
Experimental Study ◽  
Power Consumption ◽  
Clear Water ◽  
Blade Angle ◽  
Flow Rates ◽  
Blade Number ◽  
Outlet Angle ◽  
Vortex Pump ◽  
Efficiency Losses ◽  
Angle Blade

This paper analyzes the clogging behavior of a vortex pump with different impeller designs. The influence of blade outlet angle, blade number, and impeller diameter were tested. Non-woven textiles in different concentrations served as the clogging material. The results suggest that a smaller outlet blade angle, a higher blade number, and a larger impeller diameter allow pumping more textiles. Impellers that were capable of pumping more textiles, however, were less efficient. Overall, pumping textiles causes efficiency losses. However, this could not be only related to increased power consumption. Flow rates under clogging operation were close to the flow rates under clear water operation irrespective of the amount of clogging material and the impellers design. Further, in all tests clogging material accumulated at the suction mouth in the casing.

scholarly journals An advanced frequent closed sequences using BIDE

2018 ◽  
Vol 7 (2.20) ◽  
pp. 101
Author(s):  
K Vineela ◽  
M V.B.T. Santhi ◽  
N V.V. Gowtham Srujan ◽  
V Ashok
Keyword(s):  
Experimental Study ◽  
Search Engines ◽  
Historical Data ◽  
Search Space ◽  
Effective Algorithm ◽  
Direct Test ◽  
Test Strategy ◽  
The Past ◽  
Mining Algorithm ◽  
Parent Child Relationships

According to the past reasearches which produced few argumented stating that the frequent mining algorithm should only be closed but not frequent, as it not only results in compact but also complete results, and also in greater effectiveness. Most of the previous algorithms have mainly provided a direct test strategy to detect. In this article, we provide an Advanced BIDE, which is an effective algorithm used for processing query methods frequently closed. BI-Directional extension algorithm is better in pruning or filtering the search space when compared to any other algorithm. It is related to the calculation of frequent samples of search engines by parent-child relationships. An experimental study based on a variety of real historical data demonstrates the effectiveness and measurability of A-BIDE on the known alternatives of the past. It can also be scaled in terms of size of a query. 

Philosophy of Neuroscience

2016 ◽  
Author(s):  
Adina L. Roskies ◽  
Carl F. Craver
Keyword(s):  
Experimental Study ◽  
Experimental Techniques ◽  
Central Research ◽  
Philosophy Of Neuroscience ◽  
The Past ◽  
Research Areas ◽  
Potential Impact ◽  
Rich Material ◽  
The Mind ◽  
The Brain

The experimental study of the brain has exploded in the past several decades, providing rich material for both philosophers of science and philosophers of mind. In this chapter, the authors summarize some central research areas in philosophy of neuroscience. Some of these areas focus on the internal practice of neuroscience, that is, on the assumptions underlying experimental techniques, the accepted structures of explanations, the goals of integrating disciplines, and the possibility of a unified science of the mind-brain. Other areas focus outwards on the potential impact that neuroscience is having on our conception of the mind and its place in nature.

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