Influence of Baffle Block Arrangements and Downstream Weir Slope on Hydraulic Jump and Energy Dissipation on Solid-Roller Bucket Stilling Basins | Chapter 2 | Engineering Research: Perspectives on Recent Advances Vol. 7

Stilling basin is an alternative water work to reduce the scour, and it is usually supplemented by baffle blocks or defence blocks to increase the effectiveness of the energy dissipater. Baffle walls and blocks are often used to stabilise the jump, decrease its length, and increase the energy dissipation. Performance of baffle walls and blocks in free hydraulic jumps has been studied by numerous researchers. Weir is a water structure built crossing a river to elevate the water level or the channel that will be directed to the irrigation network. The rise in water level due to damming will result in rapid flow downstream. The change of flow from supercritical to subcritical will create a hydraulic jump. To reduce the energy contained in the flow, it is necessary to build an energy dissipater, which is the stilling basin. This study investigates the influence of downstream weir slope and the influence of baffle block arrangement on hydraulic jumps and energy dissipation on the solid-roller bucket. The research was conducted at the Hydraulics Laboratory of the Civil Engineering Department, Faculty of Engineering, UMS. This study used an open flume with dimensions of 30x60x1000 cm with a channel bed slope of 0.0058, an ogee spillway with a downward slope of 1: 4, 2: 4, 3: 4, 4: 4, and a solid-roller bucket stilling basin with baffle blocks of 5/12 R. The shape of the baffle blocks was cubical. The study was conducted on sixteen treatments (downstream slope and placement baffle blocks) with four variations of water discharge, in which the flow turbulence, the length of the whirlpool and energy loss of each discharge were tested. The spillway was designed using maximum discharge to obtain various flows. The findings showed that the increasing flow triggers greater turbulence, the length of the hydraulic jump downstream of the vortex, and a smaller value of the percentage of energy loss. Additionally, the most effective baffle block arrangement in reducing turbulence and hydraulic jumps is the one that is placed at the centre of the curved radius. Moreover, the efficiency of energy loss increases with reduced discharge variation; the treatment without baffle blocks is the most effective. With the same flow rate of the downstream body weir variation, there is an insignificant difference in the flow turbulence and energy loss except for the hydraulic jump length, which is the most effective 4: 4 slope. Further research can explore scouring effects at the downstream vortex, incorporating diverse forms of baffle block shapes, weir slopes, and weir heights for comprehensive analysis.

 

 

Author (s) Details

Jaji Abdurrosyid
Department of Civil Engineering, Engineering Faculty, Universitas Muhammadiyah Surakarta, Jl. A. Yani Tromol Pos 1, Pabelan Surakarta 57102, Indonesia.

 

Gurawan Djati Wibowo
Department of Civil Engineering, Engineering Faculty, Universitas Muhammadiyah Surakarta, Jl. A. Yani Tromol Pos 1, Pabelan Surakarta 57102, Indonesia.

 

Ika Setiyaningsih
Department of Civil Engineering, Engineering Faculty, Universitas Muhammadiyah Surakarta, Jl. A. Yani Tromol Pos 1, Pabelan Surakarta 57102, Indonesia.

 

Pembra Juned Adipura
Department of Civil Engineering, Engineering Faculty, Universitas Muhammadiyah Surakarta, Jl. A. Yani Tromol Pos 1, Pabelan Surakarta 57102, Indonesia.

 

Please see the book here:- https://doi.org/10.9734/bpi/erpra/v7/5273

New Perspectives on the Design of Stilling Basins | Chapter 5 | Theory and Applications of Engineering Research Vol. 6

In the design of hydraulic structures, the water velocity should be maintained at acceptable levels. The high velocity of water in an earthen channel or a natural river causes erosion of the channel bed and walls, which may cause irreparable damage to the facilities adjacent to the river. Also, in many cases, factors such as the steep slope of the channel floor, the large energy difference between two sections, the free fall of water, or the kinetic energy of the water flow is more than expected. This inevitably requires designing structures to reduce the kinetic energy. Such hydraulic facilities are called energy dissipation structures. Different types of energy dissipaters are available, the most common of which are stilling basins. With stilling basins, the flow energy is depleted by the hydraulic jump and the creation of strong turbulence in the stilling basin. For a better understanding of the energy available in the water velocity at the toe of the spillway, we can refer to the Grand Coulee dam. This dam was built on the Columbia River in America. The designed discharge of the dam spillway is 28,320 m3/s and the upstream and downstream water levels for this discharge are 393.8 and 308.23 m, respectively. If it is assumed that the energy loss on the spillway is insignificant, the energy of the water downstream of the spillway is equal to 23 GW according to the relation E=pgQH, where H is the difference in water level between the upstream and downstream sections. If the energy is not restrained properly, even the best conditioned downstream stone protection will undergo severe erosion. The design and construction of stilling basins downstream of dam spillways are one of the most common methods of water energy control and is the subject of this study.

Author(s) Details:

Farzin Salmasi,
Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz- Iran.

John Abraham,
University of St. Thomas, Minnesota, School of Engineering 2115 Summit Avenue St. Paul, Minnesota 55105, USA.

Please see the link here: https://stm.bookpi.org/TAER-V6/article/view/13373

Determination of Stilling Basin Invert Elevation and Its Effect on Controlling Hydraulic Jumps| Chapter 5 | Techniques and Innovation in Engineering Research Vol. 2

 When water is released over chutes or spillways, potential energy becomes kinetic energy. It is necessary to discharge this energy to reduce the risk of serious erosion of the riverbed downstream and foundation deterioration, both of which might cause the spillway and dam to fall. Energy dissipators must be employed in order to accomplish this goal by first transforming the energy into a highly turbulent flow, then into thermal energy. To discharge surplus energy, a variety of methods can be used, including stilling basins. For example, creating a hydraulic leap in the stilling basin will do this. The calculation of the stilling basin inversion elevation in relation to the elevation of the upstream water, the design discharge, and the elevation of the downstream water and tail water is described in this study using a straightforward method. Very few examples are provided to demonstrate the design procedure's possibilities.

Author(s) Details:

Farzin F. Salmasi,
Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.

John Abraham
University of St. Thomas, Minnesota, School of Engineering 2115 Summit Avenue St. Paul, Minnesota 55105, USA.

Please see the link here: https://stm.bookpi.org/TAIER-V2/article/view/8273

Development of Stilling Basin Model at Zero Depth of Pipe Outlet to Basin Floor: An Advanced Research | Chapter 3 | New Approaches in Engineering Research Vol. 16

 The analysis of a new Stilling Basin Model for non-circular pipe outlets with the outlet at zero depth from the basin bottom is presented in this chapter. After testing twenty-four models with various appurtenances such as impact walls, intermediate sills, and end sills, evolution was carried out. The Stilling Basin Model was put to the test for a non-circular pipe exit with a Froude number of 3.85. All models were tested using the identical bed materials, with the tail water depth remaining the same as the typical depth and the test length remaining the same at 45 minutes for all models. Scour parameters were measured after a forty-minute test run, and model performance was assessed by computing the Scouring index. For each test run, the Scour indexes following the end sill were estimated. After testing, it was discovered that a newly developed stilling basin model with appurtenances of a rectangular intermediate sill with a cross section of 0.5 d width and 1 d height, an impact wall with dimensions of 1 d x 2.2 d, and a triangular end sill with a cross section of 1 d width and 1 d height at a basin length of 6.4 d performed better than other tested models with zero depth of pipe outlet from basin floor. In comparison to the USBR VI stilling basin model, the new created Stilling Basin Model is 49 percent more efficient, and the stilling basin length is lowered by 23 percent. Thus, when compared to the USBR VI Stilling Basin Model at zero depth of pipe outlet, this model emerges as the best Stilling Basin Model among all other examined models since it is efficient and affordable.

Author(S) Details

H. L. Tiwari
Civil Engineering Department, MANIT, Bhopal, India.

M. S. Hora
Civil Engineering Department, MANIT, Bhopal, India

View Book:- https://stm.bookpi.org/NAER-V16/article/view/4056