Free Surface Flow Profile and Fluctuations of a Circular Hydraulic Jump Formed by an Impinging Jet

1995 ◽  
Vol 117 (4) ◽  
pp. 677-682 ◽  
Author(s):  
J. W. Stevens
Keyword(s):  
Free Surface ◽  
Hydraulic Jump ◽  
Surface Profile ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Flow Profile ◽  
Flow Depth ◽  
Supercritical Flow ◽  
Jump Size ◽  
Free Surface Profile

A fine wire probe was used to make quantitative measurements of the free surface profile and surface fluctuations around the hydraulic jump formed by a normally impinging free liquid jet. Representative magnitudes of both radial and axial fluctuations were presented for two nozzle sizes and several jet Reynolds numbers and subcritical flow depths. The results were compared to previous measurements of the supercritical flow depth and to theoretical predictions of the circular hydraulic jump size. The agreement appeared reasonable for the supercritical flow depth while the analytical expressions predicted a shorter hydraulic jump than that found by the measurements for the same supercritical flow conditions.

scholarly journals Meshless particle modelling of free surface flow over spillways

2015 ◽  
Vol 18 (2) ◽  
pp. 354-370 ◽  
Author(s):  
Ehsan Jafari-Nodoushan ◽  
Khosrow Hosseini ◽  
Ahmad Shakibaeinia ◽  
Seyed-Farhad Mousavi
Keyword(s):  
Free Surface ◽  
Surface Profile ◽  
Particle Method ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Weakly Compressible ◽  
Wall Boundary Conditions ◽  
Free Surface Profile ◽  
Moving Particle ◽  
Lagrangian Particle Method

A meshless Lagrangian (particle) method based on the weakly compressible moving particle semi-implicit formulation (WC-MPS) is developed and analysed for simulation of flow over spillways. To improve the accuracy of the model for pressure and velocity calculation, some modifications are proposed and evaluated for the inflow and wall boundary conditions implementation methods. The final model is applied for simulation of flow over the 45° and 60° ogee spillways (with different inflow rates) and also shallow flow over a spillway-like curved bed channel. To evaluate the model, the numerical results of free surface profile and velocity and pressure field are compared with the available experimental measurements. Comparisons show the results’ accuracy of the developed model and proposed improvements. The results of this study will not only provide a reliable numerical tool for modelling of flow over spillways, but also provide an insight for better understating flow pattern over these hydraulic structures.

Two-dimensional natural element analysis of double-free surface flow under a radial gate

2012 ◽  
Vol 39 (6) ◽  
pp. 643-653 ◽  
Author(s):  
Farhang Daneshmand ◽  
S.A. Samad Javanmard ◽  
Jan F. Adamowski ◽  
Tahereh Liaghat ◽  
Mohammad Mohsen Moshksar
Keyword(s):  
Free Surface ◽  
Surface Profile ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Element Analysis ◽  
Pressure Distributions ◽  
Free Surface Profile ◽  
Natural Element ◽  
Gravity Driven ◽  
Radial Gate

The gravity-driven free surface flow problems for which both the solid and free surface boundaries are highly curved are very difficult to solve. A computational scheme using a variable domain and a fixed domain natural element method (NEM) is developed in the present study for the computation of the free surface profile, velocity and pressure distributions, and the flow rate of a 2D gravity fluid flow through a conduit and under a radial gate. The problem involves two highly curved unknown free surfaces and arbitrary curved-shaped boundaries. These features make the problem more complicated than flow under a sluice gate or over a weir. The fluid is assumed to be inviscid and incompressible and the results obtained are confirmed by conducting a hydraulic model test. The results are in agreement with other flow solutions for free surface profiles and pressure distributions.

scholarly journals Free-surface flow due to a source submerged in a fluid of infinite depth with two stagnant regions

1993 ◽  
Vol 34 (3) ◽  
pp. 368-376 ◽  
Author(s):  
Hocine Mekias ◽  
Jean-Marc Vanden-Broeck
Keyword(s):  
Free Surface ◽  
Surface Profile ◽  
Free Surface Flow ◽  
Shear Layers ◽  
Free Surface Flows ◽  
Surface Flow ◽  
Surface Flows ◽  
Infinite Depth ◽  
Free Surface Profile ◽  
Series Truncation Method

AbstractTwo-dimensional free-surface flows produced by a submerged source in a fluid of infinite depth are considered. It is assumed that the point on the free surface just above the source is a stagnation point and that the fluid outside two shear layers is at rest. The free-surface profile and the shape of the shear layers are determined numerically by using a series-truncation method. It is shown that there is a solution for each value of the Froude number F > 0. When F tends to infinity, the flow also describes a thin jet impinging in a fluid at rest.

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.

Classical hydraulic jump: free surface profile

1993 ◽  
Vol 20 (3) ◽  
pp. 536-539 ◽  
Author(s):  
Willi H. Hager
Keyword(s):  
Free Surface ◽  
Channel Flow ◽  
Hydraulic Jump ◽  
Simple Formula ◽  
Open Channel ◽  
Surface Profile ◽  
Novel Approach ◽  
Flow Hydraulics ◽  
Channel Surface ◽  
Free Surface Profile

Based on a large number of experiments, a simple formula is developed for the time-averaged free surface profile of a classical hydraulic jump. This novel approach is based on the length of the roller. The resulting surface profile fits the data well for usual inflow Froude numbers in the range of 2 to 10. Key words: backwater, channel flow, hydraulics, open channel, surface profile.

scholarly journals SPH Open Boundary Simulation of Free-Surface Flow Over Ogee-crested Spillway

2021 ◽  
Vol 28 (2) ◽  
pp. 137-151
Author(s):  
Rizgar Karim ◽  
Jowhar Mohammad
Keyword(s):  
Free Surface ◽  
Open Source ◽  
Water Surface ◽  
Surface Profile ◽  
Free Surface Flow ◽  
The United States ◽  
Surface Flow ◽  
Absolute Difference ◽  
Open Boundary ◽  
Water Surface Profile

This study was conducted to compare water surface profiles with standard ogeecrested spillways. Different methods were used, such as (experimental models, numerical models, and design nomographs for the United States Army Corps of Engineers, USACE). In accordance with the USACE specifications, three different models were constructed from rigid foam and then installed in a testing flume. The water surface profile has been recorded for these models with different design heads. For modeling the experimental model configurations, a numerical model based on the smoothed particle hydrodynamics (SPH) technique was used and is developed to simulate the water surface profile of the flow over the ogee-crested spillway. A 2D SPHysics open-source software has been used in this study, using the SPH formulation to model fluid flow, developing the SPH boundary procedure to handle open-boundary simulations, and modifying the open-source SPHysics code for this purpose. The maximum absolute difference between the measured and computed results of the water surface profile for all head ratios of (H/Hd), does not exceed 4.63% at the crest region, the numerical results for the water surface profile showed good agreement with the physical model results. The results obtained experimentally and numerically by SPH are compared with the CFD results in order to be more reassuring from the results. Additional comparisons were made using interpolated data from USACE, Waterways Experiment Station (WES), and design nomographs. The SPH technique is considered very promising and effective for free surface flow applications.

Discharge Coefficient of Rectangular Side Weirs on Circular Channels

2016 ◽  
Vol 17 (7-8) ◽  
pp. 391-399 ◽  
Author(s):  
Hamed Azimi ◽  
Saeid Shabanlou ◽  
Isa Ebtehaj ◽  
Hossein Bonakdari
Keyword(s):  
Free Surface ◽  
Numerical Model ◽  
Flow Regime ◽  
Discharge Coefficient ◽  
Three Dimensional ◽  
Free Surface Flow ◽  
Energy Difference ◽  
Surface Flow ◽  
Side Weir ◽  
Supercritical Flow

AbstractIn this study, the flow turbulence and variations of the supercritical free surface flow in a circular channel along a side weir are simulated as three dimensional using the RNG k-ε turbulence model and volume of fluid (VOF) scheme. Comparison between the numerical model and experimental measurements shows that the numerical model simulates the free surface flow with good accuracy. According to the numerical model results, the specific energy variations along the side weir for the supercritical flow regime are almost constant and the energy drop is not significant but by increasing the side weir length the energy difference between the side weir upstream and downstream increases. Next, using the nonlinear regression (NLR) and analysis of the simulation results, some relationships for calculating the discharge coefficient of side weir on circular channels in supercritical flow regime are provided.

Potential flow solution for a free surface flow past a sudden slope change

2004 ◽  
Vol 31 (4) ◽  
pp. 553-560 ◽  
Author(s):  
A R Zarrati ◽  
Yee-Chung Jin ◽  
A Shanehsaz-zadeh ◽  
F Ahadi
Keyword(s):  
Free Surface ◽  
Pressure Distribution ◽  
Analytical Model ◽  
Potential Flow ◽  
Sudden Change ◽  
Surface Profile ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Flow Past ◽  
Model Predictions

An analytical model was developed to calculate the pressure distribution in a free surface flow past a sudden change in channel slope. A conformal transformation technique was used to solve the problem analytically in a way that there is no need for trial and error to find the location of the free surface. Two methods were employed for this simulation: flow at a corner and free streamline theory. It was shown that free streamline theory is more accurate. Experiments were conducted to verify the ability of the analytical model to calculate the pressure distribution in a channel with a sudden change in slope. Slope changes of 6.22°, 10°, and 15° were tested with various flow discharges. The analytical model predictions of pressure distribution along the channel bed and with depth agreed well with the experimental measurements. Pressures up to 25 times the hydrostatic pressure were experimentally measured near the point of sudden change in slope. These pressures were reproduced by the model. The analytical model predictions of the water surface profile over a ramp in a prototype spillway were compared with those of a numerical model. The comparison showed a good agreement.Key words: pressure distribution, free surface flow, analytical model, chute spillway, aerator ramp, potential flow.

Hydraulic jump in channel contraction

1995 ◽  
Vol 22 (5) ◽  
pp. 925-933 ◽  
Author(s):  
Y. Yasuda ◽  
Willi H. Hager
Keyword(s):  
Hydraulic Jump ◽  
Surface Profile ◽  
Momentum Equation ◽  
Flow Depth ◽  
Contraction Rate ◽  
Substantial Agreement ◽  
Limit Condition ◽  
Supercritical Flow ◽  
Small Contraction ◽  
Important Design

The hydraulic jump in a linearly contracting channel is studied in relation to choking flow. For a contraction intended to perform under supercritical flow, choking is an important design consideration because of the increase of flow depth and modified upstream conditions. Based on the momentum equation, a relation for the sequent depths ratio is determined and verified with extended experiments. Further, the mechanisms of both hydraulic jump and the choking flow are described. The wall surface profile is shown to be similar and equal to the profile of the classical hydraulic jump for a relatively small contraction rate. The lengths of roller and jump are determined, and substantial agreement with the classical jump is again found. The choking of a channel contraction is discussed as the limit condition of the hydraulic jump. A simplified model is shown to agree with observations. A design equation for choking is proposed. Key words: channel, choking, contraction, hydraulic jump, supercritical flow, water flow.

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