Radial flow stilling basins with baffle blocks

1989 ◽  
Vol 16 (4) ◽  
pp. 489-497 ◽  
Author(s):  
Peter C. Nettleton ◽  
John A. McCorquodale
Keyword(s):  
Key Words ◽  
Hydraulic Jump ◽  
Water Surface ◽  
Radial Flow ◽  
Surface Profile ◽  
Hydraulic Jumps ◽  
Bureau Of Reclamation ◽  
Stilling Basin ◽  
Jump Length ◽  
Stilling Basins

A total of 120 tests of forced radial flow hydraulic jumps have been analyzed in order to develop curves and equations for the design of radial stilling basins. The jump depth, the water surface profile, wave amplitudes, the allowable flare angle, and the jump length are defined in terms of entrance conditions, the baffle position, and the baffle height. An example design is given and compared with a USBR (U.S. Bureau of Reclamation) Type III stilling basin. Key words: forced hydraulic jump, radial flow, design, stilling basins, baffles, radial hydraulic jump, circular hydraulic jump.

scholarly journals Experimental Characterization of the Hydraulic Jump Profile and Velocity Distribution in a Stilling Basin Physical Model

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1758
Author(s):  
Juan Macián-Pérez ◽  
Francisco Vallés-Morán ◽  
Santiago Sánchez-Gómez ◽  
Marco De-Rossi-Estrada ◽  
Rafael García-Bartual
Keyword(s):  
Free Surface ◽  
Energy Dissipation ◽  
Velocity Distribution ◽  
Physical Model ◽  
Hydraulic Jump ◽  
Surface Profile ◽  
Air Entrainment ◽  
Stilling Basin ◽  
Free Surface Profile ◽  
Stilling Basins

The study of the hydraulic jump developed in stilling basins is complex to a high degree due to the intense velocity and pressure fluctuations and the significant air entrainment. It is this complexity, bound to the practical interest in stilling basins for energy dissipation purposes, which brings the importance of physical modeling into the spotlight. However, despite the importance of stilling basins in engineering, bibliographic studies have traditionally focused on the classical hydraulic jump. Therefore, the objective of this research was to study the characteristics of the hydraulic jump in a typified USBR II stilling basin, through a physical model. The free surface profile and the velocity distribution of the hydraulic jump developed within this structure were analyzed in the model. To this end, an experimental campaign was carried out, assessing the performance of both, innovative techniques such as the time-of-flight camera and traditional instrumentation like the Pitot tube. The results showed a satisfactory representation of the free surface profile and the velocity distribution, despite some discussed limitations. Furthermore, the instrumentation employed revealed the important influence of the energy dissipation devices on the flow properties. In particular, relevant differences were found for the hydraulic jump shape and the maximum velocity positions within the measured vertical profiles, when compared to classical hydraulic jumps.

scholarly journals Analysis of the Flow in a Typified USBR II Stilling Basin through a Numerical and Physical Modeling Approach

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 227 ◽  
Author(s):  
Juan Francisco Macián-Pérez ◽  
Rafael García-Bartual ◽  
Boris Huber ◽  
Arnau Bayon ◽  
Francisco José Vallés-Morán
Keyword(s):  
Physical Model ◽  
Hydraulic Jump ◽  
Numerical Approach ◽  
Free Surface Flows ◽  
United States Bureau ◽  
Bureau Of Reclamation ◽  
Stilling Basin ◽  
Modeling Approach ◽  
Stilling Basins ◽  
Energy Dissipation Devices

Adaptation of stilling basins to higher discharges than those considered for their design implies deep knowledge of the flow developed in these structures. To this end, the hydraulic jump occurring in a typified United States Bureau of Reclamation Type II (USBR II) stilling basin was analyzed using a numerical and experimental modeling approach. A reduced-scale physical model to conduct an experimental campaign was built and a numerical computational fluid dynamics (CFD) model was prepared to carry out the corresponding simulations. Both models were able to successfully reproduce the case study in terms of hydraulic jump shape, velocity profiles, and pressure distributions. The analysis revealed not only similarities to the flow in classical hydraulic jumps but also the influence of the energy dissipation devices existing in the stilling basin, all in good agreement with bibliographical information, despite some slight differences. Furthermore, the void fraction distribution was analyzed, showing satisfactory performance of the physical model, although the numerical approach presented some limitations to adequately represent the flow aeration mechanisms, which are discussed herein. Overall, the presented modeling approach can be considered as a useful tool to address the analysis of free surface flows occurring in stilling basins.

USBR Type III and Type IV Stilling Basins and Rock Aprons Associated with Stepped Chutes

2018 ◽  
Vol 34 (2) ◽  
pp. 389-394
Author(s):  
Sherry L. Hunt ◽  
Kem C. Kadavy
Keyword(s):  
Research Unit ◽  
Stepped Spillways ◽  
Engineering Research ◽  
Bureau Of Reclamation ◽  
Stilling Basin ◽  
Type Iii ◽  
Design Engineers ◽  
Type Iv ◽  
Rock Stability ◽  
Stilling Basins

Abstract. Stilling basins are commonly used as energy dissipators for structural chutes. Classical research conducted by scientists of the U. S. Bureau of Reclamation (USBR) led to the development of design criteria for a variety of stilling basin configurations as the outlet works for smooth chutes, but little is known about the performance of these dissipators when paired with stepped chutes. Research at the USDA-ARS Hydraulic Engineering Research Unit (HERU) in Stillwater, Oklahoma, was conducted on USBR Type III and Type IV stilling basins with rock aprons located downstream of a near prototype stepped chute. Data indicates Froude numbers based on the incoming clear water flow depth to the stilling basin range from 3.3 = F = 5.5. Visual observations noted during the tests indicate acceptable performance of the Type III and Type IV stilling basins when operated at recommended or greater tailwater settings as set forth by the USBR. Three methods, the Isbash, USBR, and USGS, were chosen for evaluating the rock stability of the rock aprons placed downstream of the endsill of the stilling basins used in association with stepped chutes. Data indicate each method is suitable for riprap sizing of the rock apron. The intent of this research is to provide design engineers with knowledge regarding the performance of USBR Type III and Type IV stilling basins with rock aprons designed in conjunction with stepped chutes. Keywords: Dam safety, Embankment dams, Energy dissipation, Rock apron, Roller compacted concrete, Stepped spillways, Stilling basin.

scholarly journals Numerical Simulation of Hydraulic Jump over Rough Beds

2020 ◽  
Author(s):  
Saman Nikmehr ◽  
Younes Aminpour
Keyword(s):  
Numerical Model ◽  
Velocity Distribution ◽  
Hydraulic Jump ◽  
Surface Profile ◽  
Jump Length ◽  
Rough Bed ◽  
Sequent Depth ◽  
Rough Beds ◽  
Different Characteristics ◽  
Good Agreement

In this study, the hydraulic jumps over rough beds are numerically simulated. In order to calibrate the numerical model, the experimental data were used, which performed in a rectangular flume in various roughness arrangements and different Froude numbers. The effect of the distance (s) and the height (t) of the roughness on different characteristics of the hydraulic jump, including the sequent depth ratio, water surface profile, jump’s length, roller’s length, and velocity distribution were evaluated and compared. The results showed that the numerical model is fairly well able to simulate the hydraulic jump characteristics. The results also showed that the height and distance of roughness slightly reduced the sequent depth ratios for all Froude numbers. Also, the hydraulic jump length is reduced at the presence of the rough bed. Velocity profiles in different experiments were similar and there was a good agreement between simulated and measured results. Also, increasing the distance and the height of the roughness will slow down the velocity near the bed, increase the shear stress, and increase the gradient of the velocity distribution near the bed.

scholarly journals Pressure Fluctuations in the Spatial Hydraulic Jump in Stilling Basins with Different Expansion Ratio

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 60
Author(s):  
Nasrin Hassanpour ◽  
Ali Hosseinzadeh Dalir ◽  
Arnau Bayon ◽  
Milad Abdollahpour
Keyword(s):  
Hydraulic Jump ◽  
Laboratory Tests ◽  
Pressure Fluctuations ◽  
Expansion Ratio ◽  
Hydraulic Jumps ◽  
Extreme Pressure ◽  
Flow Conditions ◽  
Stilling Basins ◽  
Channel Expansion ◽  
Shed Light

Pressure fluctuations are a key issue in hydraulic engineering. However, despite the large number of studies on the topic, their role in spatial hydraulic jumps is not yet fully understood. The results herein shed light on the formation of eddies and the derived pressure fluctuations in stilling basins with different expansion ratios. Laboratory tests are conducted in a horizontal rectangular flume with 0.5 m width and 10 m length. The range of approaching Froude numbers spans from 6.4 to 12.5 and the channel expansion ratios are 0.4, 0.6, 0.8, and 1. The effects of approaching flow conditions and expansion ratios are thoroughly analyzed, focusing on the dimensionless standard deviation of pressure fluctuations and extreme pressure fluctuations. The results reveal that these variables show a clear dependence on the Froude number and the distance to the hydraulic jump toe. The maximum values of extreme pressure fluctuations occur in the range 0.609<X<3.385, where X is dimensionless distance from the toe of the hydraulic jump, which makes it highly advisable to reinforce the bed of stilling basins within this range.

scholarly journals Experimental study and modeling of hydraulic jump for a suddenly expanding stilling basin using different hybrid algorithms

2021 ◽  
Author(s):  
Enes Gul ◽  
O. Faruk Dursun ◽  
Abdolmajid Mohammadian
Keyword(s):  
Experimental Study ◽  
Hydraulic Jump ◽  
Imperialist Competitive Algorithm ◽  
Expansion Ratio ◽  
Stilling Basin ◽  
Jump Length ◽  
Depth Ratio ◽  
Input Variables ◽  
Sequent Depth ◽  
Learning Machine

Abstract Hydraulic jump is a highly important phenomenon for dissipation of energy. This event, which involves flow regime change, can occur in many different types of stilling basins. In this study, hydraulic jump characteristics such as relative jump length and sequent depth ratio occurring in a suddenly expanding stilling basin were estimated using hybrid Extreme Learning Machine (ELM). To hybridize ELM, Imperialist Competitive Algorithm (ICA), Firefly Algorithm (FA) and Particle Swarm Optimization (PSO) metaheuristic algorithms were implemented. In addition, six different models were established to determine effective dimensionless (relative) input variables. A new dataset was constructed by adding the data obtained from the experimental study in the present research to the data obtained from the literature. The performance of each model was evaluated using k-fold cross validation. Results showed that ICA hybridization slightly outperformed FA and PSO methods. Considering relative input parameters, Froude number (Fr), expansion ratio (B) and relative sill height (S), and effective input combinations were Fr – B– S and Fr – B for the prediction of the sequent depth ratio (Y) and relative hydraulic jump length (Lj/h1), respectively.

scholarly journals Uncertainty analyses regarding evaluating effective parameters on the hydraulic jump characteristics of different shape channels

2021 ◽  
Author(s):  
Kiyoumars Roushangar ◽  
Farzin Homayounfar ◽  
Roghayeh Ghasempour
Keyword(s):  
Hydraulic Jump ◽  
Gaussian Process Regression ◽  
Support Vector ◽  
Hydraulic Jumps ◽  
Empirical Equations ◽  
Effective Parameters ◽  
Jump Length ◽  
Depth Ratio ◽  
Sequent Depth ◽  
Semi Empirical

Abstract The hydraulic jump phenomenon is a beneficial tool in open channels for dissipating the extra energy of the flow. The sequent depth ratio and hydraulic jump length critically contribute to designing hydraulic structures. In this research, the capability of Support Vector Machine (SVM) and Gaussian Process Regression (GPR) as kernel-based approaches was evaluated to estimate the features of submerged and free hydraulic jumps in channels with rough elements and various shapes, followed by comparing the findings of GPR and SVM models and the semi-empirical equations. The results represented the effect of the geometry (i.e., steps and roughness elements) of the applied appurtenances on hydraulic jump features in channels with appurtenances. Moreover, the findings confirmed the significance of the upstream Froude number in the sequent depth ratio estimating in submerged and free hydraulic jumps. In addition, the immersion was the highest contributing variable regarding the submerged jump length on sloped smooth bed and horizontal channels. Based on the comparisons among kernel-based approaches and the semi-empirical equations, kernel-based models showed better performance than these equations. Finally, an uncertainty analysis was conducted to assess the dependability of the best applied model. The results revealed that the GRP model possesses an acceptable level of uncertainty in the modeling process.

Laboratory study of stilling basin using trapezoidal bed elements

2020 ◽  
Vol 29 (4) ◽  
pp. 409-420
Author(s):  
Thair Al-Fatlawi ◽  
Nassrin Al-Mansori ◽  
Nariman Othman
Keyword(s):  
Energy Dissipation ◽  
Laboratory Study ◽  
Hydraulic Jump ◽  
Stilling Basin ◽  
Smooth Model ◽  
Stilling Basins ◽  
Spillway Structures ◽  
Baffle Block ◽  
Pressure Driven

When designing dam spillway structures, the most significant consideration is the energy dissipation arrangements. Different varieties of baffle blocks and stilling basins have been used in this context. However, the hydraulic jump form of stilling basin is considered to be the most suitable. The main objective of this research was to introduce four different baffle block shapes (models arranged from A to D, installed at slopes 0.00, 0.04, 0.06 and 0.08 in the stilling basins). To illustrate the consequences for the qualities of pressure-driven bounce, each model was attempted in the bowl. The trials applied Froude numbers between 6.5 and 9.2. The puzzle square model D provided the best outcomes compared to the models A, B, C and smooth. Model D with different models at inclines 0.00, 0.04, 0.06 and 0.08 was used to consider the impacts of perplex hinders on water driven-bounce when bed slants were changed. When the model D baffle used instead of a smooth bed at 0.08 slope, the reduction in y2 / y1 reached 12.8%, and Lj / y1 was 18.9%. Among the different bed slopes, a normal decrease in y2 / y1 ranged from approximately 10.3%, whereas the normal decrease in Lj / y1 was about 13.8% when the model D baffle was used instead of the model A baffle with a horizontal slope bed of 0.00. The results show that the new shapes led to a decrease in sequent profundity proportion and length of jump proportion; however, the energy dissipation proportion increased.

scholarly journals An evaluation of ANN methods for estimating the lengths of hydraulic jumps in U-shaped channel

2012 ◽  
Vol 15 (1) ◽  
pp. 147-154 ◽  
Author(s):  
Larbi Houichi ◽  
Noureddine Dechemi ◽  
Salim Heddam ◽  
Bachir Achour
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Hydraulic Jump ◽  
Empirical Models ◽  
Generalized Regression Neural Network ◽  
Hydraulic Jumps ◽  
Hydraulic Characteristics ◽  
Stilling Basins ◽  
High Turbulence ◽  
Predictive Strength

Modelling of hydraulic characteristics of jump using theoretical and empirical models has always been a difficult task. The length of jump may be defined as the distance measured from the toe of the jump to the location of the surface rise. Due to high turbulence this length cannot be determined easily by theory. However, it has been investigated experimentally so as to design the stilling basins with hydraulic jumps. In this work, the control of a hydraulic jump by broad-crested sills in a U-shaped channel is recalled theoretically and experimentally examined. The study begins with a multiple regression (MR) analysis. Then, and in order to model the relative lengths of hydraulic jumps, we have implemented and evaluated two different artificial neural networks (ANN): multilayer perceptron neural network (MLPNN) and generalized regression neural network (GRNN). The results demonstrate the predictive strength of GRNN and its potential to predict hydraulic problems with an adaptive spread value. However, the MLPNN model remains best classified by these indexes of performance.

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