scholarly journals Experimental Analysis of Hydraulic Jump at High Froude Numbers

2021 ◽  
Author(s):  
Oguz Simsek ◽  
Mevlut Sami Akoz ◽  
Nazire Goksu Soydan Oksal
Keyword(s):  
Turbulence Intensity ◽  
Hydraulic Jump ◽  
Laser Doppler Anemometry ◽  
Relative Height ◽  
Flow Conditions ◽  
Structural Configuration ◽  
Stilling Basin ◽  
Rapid Transition ◽  
Sill Height ◽  
Energy Dissipation Ratio

Abstract The hydraulic jump is a rapid transition state from supercritical to subcritical flow that occurs commonly in rivers, prismatic channels and downstream of spillways. In this study, the characteristics of the hydraulic jump in a stilling basin downstream of the spillway chute channel with the slopes of α = 12o and 30o were investigated experimentally for different Froude numbers of incoming flow, Fr1 = 7, 7.5, 8, 9, 10 and 12, and relative heights of sill in the range of 4 < hs/h1 (S) < 13 (S relative height). In the experiments, in which velocity field measured by laser Doppler Anemometry, it was particularly focused on the effects of both different structural configuration and flow conditions on the hydraulic jump and energy dissipation ratio. Experimental measurements showed that the length of hydraulic jump and the roller zone increases with the decrease of the sill height for α = 12o and 30o. In addition, the length of the hydraulic jump and roller zone increased with decreasing Froude numbers. The turbulence intensity in the jump region was determined to be greater than the turbulence intensity in the region near the bottom of stilling basin. The turbulence intensity, in general, tended to decrease with decreasing Froude number.

scholarly journals Hydraulic model experiment of energy dissipation on the horizontal and USBR II stilling basin

2021 ◽  
Vol 930 (1) ◽  
pp. 012029
Author(s):  
V Dermawan ◽  
Suhardjono ◽  
L Prasetyorini ◽  
S Anam
Keyword(s):  
Energy Dissipation ◽  
Hydraulic Jump ◽  
Control Point ◽  
Hydraulic Model ◽  
Flow Depth ◽  
Flow Conditions ◽  
Depth Measurement ◽  
Stilling Basin ◽  
Flow Energy ◽  
Starting Point

Abstract Flow conditions on overflow systems can result in construction failure, mainly due to the high flow energy. Stilling basin at downstream of the spillway is useful for reducing flow energy. It can reduce the destructive force of water flow. Controlling the hydraulic jump is an important part that includes the jump’s energy, length, and height. The physical hydraulic model was carried out with several series, by making a series of bottom lowering of horizontal and USBR II stilling basin. The experimental study is expected to represent flow behavior in the overflow system regarding flow conditions and energy dissipation. Based on the analytical calculation of flow velocity, the amount of flow energy that occurs at each control point is calculated. The control points are the starting point of the spillway, the chute way toe, and flow depth after the hydraulic jump. The energy loss can be calculated for each control point, while the efficiency of energy dissipation on stilling basin is calculated at the downstream flow depth after the hydraulic jump. Velocity calculated by dividing discharge per unit width by water depth which is based on the flow depth measurement data in the hydraulic model.

scholarly journals Effect of baffle block configurations on characteristics of hydraulic jump in adverse stilling basins

2018 ◽  
Vol 162 ◽  
pp. 03005
Author(s):  
Ali Abbas ◽  
Haider Alwash ◽  
Ali Mahmood
Keyword(s):  
Energy Dissipation ◽  
Hydraulic Jump ◽  
Block Model ◽  
Double Row ◽  
Stilling Basin ◽  
Depth Ratio ◽  
Stilling Basins ◽  
Sequent Depth ◽  
Baffle Block ◽  
Energy Dissipation Ratio

The construction of stilling basin with adverse slope change the characteristics of hydraulic jump such as sequent depth ratio, length of jump ratio, length of roller and energy dissipation ratio, consequently the dimensions of stilling basin are changed, also using baffle blocks with different configurations develop these characteristics. In this study different shapes of baffle block (models (A), (B), (C) and (D)) installed in the stilling basins at adverse slopes (- 0.03, - 0.045, - 0.06) in addition to horizontal bed, all these models are tested in the stilling basin to show their effects on the characteristics of hydraulic jump, the experiments applied for the range of Froude number (Fr1) between 3.99 and 7.48. The baffle block model (D) showed good results when compared with models (B) and (C), therefore it used with arrangement of (single and double row) and compared with baffle block model (A) at slopes (0, - 0.03, - 0.045, - 0.06) to study the effects of baffle blocks on hydraulic jump when bed slopes are changed. In general using baffle block caused a reduction in sequent depth ratio, length of jump ratio and the length of the roller, but the energy dissipation ratio increased.

ESTIMATION OF HYDRAULIC JUMP CHARACTERISTICS IN STILLING BASIN WITH GUIDE WALLS

2012 ◽  
Vol 40 (6) ◽  
pp. 1599-1609
Author(s):  
Habib A.A. ◽  
Abdel-Azim M. Ali ◽  
Abd-Allh Y.M ◽  
Saleh y.k.
Keyword(s):  
Hydraulic Jump ◽  
Stilling Basin

Comparison of Experimental and Numerical Simulations of Flow Within an Arterio-Venous Graft

2000 ◽  
Author(s):  
Paul F. Fischer ◽  
Seung Lee ◽  
Francis Loth ◽  
Hisham S. Bassiouny ◽  
Nurullah Arslan
Keyword(s):  
Flow Field ◽  
Steady Flow ◽  
Laser Doppler Anemometry ◽  
Transition To Turbulence ◽  
Flow Conditions ◽  
Venous Graft ◽  
Venous Anastomosis ◽  
Av Graft ◽  
Good Agreement

Abstract This was a study to compare computational and experimental results of flow field inside the venous anastomosis of an arteriovenous (AV) graft. Laser Doppler anemometry (LDA) measurements were conducted inside an upscaled end-to-side graft model under steady flow conditions at Reynolds number 1820 which is representative of the in vivo flow conditions inside a human AV graft. The distribution of the velocity and turbulence intensity was measured at several locations in the plane of the bifurcation. This flow field was simulated using computation fluid dynamics (CFD) and shown to be in good agreement. Under steady flow conditions, the flow field demonstrated an unsteady character (transition to turbulence).

Correlation Between LDA and Ultrasound Heart Catheter Measurements in a Stenosed Arterial Model

1995 ◽  
Vol 117 (1) ◽  
pp. 103-106 ◽  
Author(s):  
D. Liepsch ◽  
A. Poll ◽  
R. Blasini
Keyword(s):  
Cross Section ◽  
Laser Doppler Anemometry ◽  
Water Solution ◽  
Maximum Velocity ◽  
Symmetric Model ◽  
Axially Symmetric ◽  
Flow Conditions ◽  
Future Studies ◽  
Glycerine Water ◽  
Arterial Model

Ultrasound heart catheters are used to measure the velocity in coronary arteries. However, the act of introducing a catheter into the vessel disturbs the very flow being measured. We used laser Doppler anemometry to measure the velocity distribution in an axially symmetric model, both with and without a catheter inserted. The catheter reduced the center-line velocity by as much as 60 percent at a distance of 2 mm downstream from the catheter, and by as much as 25 percent at a distance of 10 mm. This means the velocity measured with an ultrasound catheter does not show the maximum velocity of the undisturbed flow in the tube center. In the constriction, however, the measured velocities with the LDA and ultrasound catheter are almost the same. Thus, catheter measurements in the stenosis achieve accurate results. The velocity profile in the stenosed areas is flattened over nearly the whole cross section. The velocity is extremely reduced only close to the wall. The measurements outside of the stenosis lead to large differences which need to be studied carefully in the future. The disturbed flow finally disappeared 15 mm downstream of the catheter. The measurements were done at steady flow using a glycerine water solution with a dynamic viscosity of 4.35m Pas. In future studies, these experiments will be repeated for pulsatile flow conditions using non-Newtonian blood-like fluids.

scholarly journals Modification of Classical Horseshoe Spillways: Experimental Study and Design Optimization

2019 ◽  
Vol 5 (10) ◽  
pp. 2093-2109
Author(s):  
Vahid Hassanzadeh Vayghan ◽  
Ali Saber ◽  
Soroosh Mortazavian
Keyword(s):  
Hydraulic Jump ◽  
Design Parameters ◽  
Hydraulic Structures ◽  
Flow Conditions ◽  
Design Factor ◽  
Flow Passage ◽  
Water Head ◽  
Cubic Polynomial ◽  
Polynomial Models ◽  
Discharge Efficiency

Investigation of the hydraulic aspects of spillways is one of the important issues regarding hydraulic structures. This study presents a modified horseshoe spillway (MHS) constructed by adding a flow passage and an internal weir in the bed of a classical horseshoe spillway (CHS). This modification increased the discharge efficiency and eliminated the rooster-tail hydraulic jump in CHSs. Eighteen laboratory-scale MHSs in various geometric sizes, six various CHSs, and a rectangular weir of the same width were constructed and tested under the same flow conditions. Results showed that in terms of discharge efficiency and water head reduction, CHSs and MHSs were superior to the rectangular weir. Compared to CHSs, the increased discharge flowrate in MHSs due to the internal weirs could further reduce the water head and thus increased their overall efficiencies. Design parameters effecting spillways’ discharge efficiencies were investigated based on dimensional analysis. The internal to external weir length ratio in MHSs was found to be a key design factor. To determine the optimal geometric design of CHS and MHS models, cubic polynomial models considering dimensionless parameters and their interactions were fitted to the experimental results. The cubic models revealed that higher discharge efficiencies in MHSs tended to occur at relatively low water heads and high internal to external weir lengths ratios.

APPROACH TO THE VOID FRACTION DISTRIBUTION WITHIN A HYDRAULIC JUMP IN A TYPIFIED USBR II STILLING BASIN

2019 ◽  
Author(s):  
JUAN FRANCISCO MACIÁN-PÉREZ ◽  
RAFAEL GARCÍA-BARTUAL ◽  
BORIS HUBER ◽  
ARNAU BAYÓN ◽  
FRANCISCO J VALLÉS MORÁN
Keyword(s):  
Void Fraction ◽  
Hydraulic Jump ◽  
Stilling Basin ◽  
Void Fraction Distribution ◽  
Fraction Distribution

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 Hydraulic optimization of corrugated stilling basin with adverse slope

2018 ◽  
Vol 19 (1) ◽  
pp. 313-322 ◽  
Author(s):  
Tooraj Honar ◽  
Nafiseh Khoramshokooh ◽  
Mohammad Reza Nikoo
Keyword(s):  
Optimization Model ◽  
Hydraulic Jump ◽  
Experimental Results ◽  
Data Driven ◽  
Design Parameters ◽  
Algorithm Optimization ◽  
Stilling Basin ◽  
Design Variables ◽  
Bed Slope ◽  
Mlp Model

Abstract In this paper, perhaps for the first time, a data-driven simulation–optimization model is developed based on experimental results to find the effects of state and decision variables on the optimum characteristics of a stilling basin with adverse slope and corrugated bed. The optimal design parameters of the stilling basin are investigated to minimize the length of the hydraulic jump and ratio of the sequent depths of the jump while the relative amount of energy loss is maximized. In order to model the relationship between design variables of the bed, the experimental results are converted to a data-driven simulation model on the basis of a multilayer perceptron (MLP) neural network. Then, the validated MLP model is used in a genetic algorithm optimization model in order to determine the optimum characteristics of the bed under the hydraulic jump considering the interaction between the bed design variables and the hydraulic parameters of the flow. Results indicate that the optimum values of bed slope and the diameter of the corrugated roughness (2r) can be considered as −0.02 and 20 millimetres, respectively.

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