scholarly journals Flow Simulation and Energy Loss Estimation in the Nappe Flow Regime of Stepped Spillways with Inclined Steps and End Sill: A Numerical Approach

2016 ◽  
Vol 2 (9) ◽  
pp. 426-437 ◽  
Author(s):  
Amirmasoud Hamedi ◽  
Mohammad Hajigholizadeh ◽  
Abbas Mansoori
Keyword(s):  
Numerical Simulation ◽  
Energy Loss ◽  
Flow Pattern ◽  
Flow Direction ◽  
Low Cost ◽  
Flow Simulation ◽  
Numerical Approach ◽  
Stepped Spillway ◽  
Stepped Spillways ◽  
Time Required

Recently, the usage of stepped spillways, as energy dissipaters, has increased and led to a reduction in the size of the stilling basin. Extensive experimental considerations, plus the high cost and extended time required for laboratory methods, are among the major issues that require precise attention to determine optimal step design. This research deals with comparing the 2-D numerical simulation and experimental description in stepped spillways equipped with inclined steps and end sill together and presents a brisk, reliable, low-cost, and non-experimental approach to designing the steps. In this new type and complicated geometry, simulation is more complicated than horizontal steps, because it needs more accuracy around the end sills. The VOF Method and the k-ε standard turbulence model are proposed to simulate the flow pattern and evaluate the energy loss over stepped spillway. Energy dissipations obtained through the numerical approach have been compared with laboratory measurements and demonstrate reasonable agreement. Also, the flow pattern, velocity vectors and flow direction resulted from numerical simulation is in a good agreement with the experimental results.

scholarly journals Comparison of Different Turbulence Models for Numerical Simulation of Pressure Distribution in V-Shaped Stepped Spillway

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Zhaoliang Bai ◽  
Jianmin Zhang
Keyword(s):  
Numerical Simulation ◽  
Pressure Distribution ◽  
Flow Pattern ◽  
Turbulence Model ◽  
Turbulence Models ◽  
Flow Regimes ◽  
Stepped Spillway ◽  
Stepped Spillways

V-shaped stepped spillway is a new shaped stepped spillway, and the pressure distribution is quite different from that of the traditional stepped spillway. In this paper, five turbulence models were used to simulate the pressure distribution in the skimming flow regimes. Through comparing with the physical value, the realizablek-εmodel had better precision in simulating the pressure distribution. Then, the flow pattern of V-shaped and traditional stepped spillways was given to illustrate the unique pressure distribution using realizablek-εturbulence model.

scholarly journals ANALISIS PENGARUH NILAI KONDUKTIVITAS HIDRAULIK DAN DISPERSIVITAS DINAMIK TERHADAP REMEDIASI AIR TANAH MENGGUNAKAN SIMULASI NUMERIK

2021 ◽  
Vol 12 (2) ◽  
pp. 107-118
Author(s):  
Agus Mochamad Ramdhan ◽  
Arifin Arifin ◽  
Erik Hermawan ◽  
Lambok M. Hutasoit
Keyword(s):  
Numerical Simulation ◽  
Sensitivity Analysis ◽  
Hydraulic Conductivity ◽  
Groundwater Remediation ◽  
Flow Simulation ◽  
Pumping Wells ◽  
Time Required ◽  
Close Distance ◽  
High Hydraulic Conductivity

Groundwater remediation is one of the solutions to restore the contaminated groundwater. This study was conducted to determine the effect of hydraulic conductivity and dynamic dispersivity on the groundwater remediation effectiveness. As a case study, in 2020, in an area located in Balikpapan, groundwater remediation will be carried out by injecting water containing NaOH through five wells and pumping it back through five wells to form a cycle. The method used is a numerical simulation consisting of groundwater flow simulation, mass transport, and sensitivity analysis. The results show that it takes 124 to 300 days for the injected NaOH to arrive at the pumping wells. The sensitivity analysis results show that when the hydraulic conductivity value is ten times greater, the time required is reduced to 84 to 172 days. Meanwhile, when the dynamic dispersivity is twice larger, the time required is reduced to 75 to 189 days. These results indicate that the groundwater remediation method will be effective for aquifers with high hydraulic conductivity and dynamic dispersivity values. For the study area, the groundwater remediation is suggested to be carried out by increasing the number of injection and pumping wells with a relatively close distance, i.e., around 10 meters, so that NaOH arrives at the pumping wells more quickly.Keywords: groundwater, remediation, hydraulic conductivity, dynamic dispersivity, numerical simulation

Using Numerical Simulation in the Optimization of the Finishing Phases in Ceramic Tiles Manufacturing

2017 ◽  
Vol 754 ◽  
pp. 127-130
Author(s):  
A. Radovanovic ◽  
M. Mladenovic ◽  
G. Campana ◽  
M. Mele
Keyword(s):  
Numerical Simulation ◽  
Finite Elements ◽  
Low Cost ◽  
Large Family ◽  
Numerical Approach ◽  
Ceramic Tiles ◽  
Fundamental Part ◽  
Complex Process ◽  
Porcelain Tiles

The Grés Porcelain stoneware surely represents a remarkable material for building inside the large family of constructive ceramics. It is appreciated in consideration of its superior properties of resistance and functionality, especially when considered respect to a relatively low cost. Billions of square meters of Grés Porcelain are produced worldwide each year, primarily in form of tiles of every dimension, thinness, color, decoration, in the way that the ceramic tile industry represents a relevant economy. But the tile manufacturing is a complex process, made by different stages and productive plants to be deeply investigated and optimized. This paper describes the use of Finite Elements for modelling and optimizing the production of Grés Porcelain tiles with special attention to the ending phases of the process, just after the treatments in kiln and realized by tool machining. The case study, used to redesign a fundamental part of a finishing machine driven by a numerical approach, is also detailed.

FLOW AND ENERGY DISSIPATION OVER ON FLAT AND POOLED STEPPED SPILLWAY

2016 ◽  
Vol 78 (8) ◽  
Author(s):  
Denik Sri Krisnayanti ◽  
Soehardjono Soehardjono ◽  
Very Dermawan ◽  
Mohammad Sholichin
Keyword(s):  
Energy Dissipation ◽  
Energy Loss ◽  
Froude Number ◽  
Relative Energy ◽  
Stepped Spillway ◽  
Dissipation Energy ◽  
Stepped Spillways ◽  
Flow Energy ◽  
Physical Study ◽  
Roughness Elements

The stepped spillway has increasingly become effective energy dissipation. The stepped spillway has been accepted to be the most powerful hydraulic structure to dissipate large flow energy downstream from spillway crest. The steps act as roughness elements significantly increase the dissipation energy rate. The physical study has performed on flat and pooled stepped spillways with a slope spillway    (θ = 45˚) and number of steps (N): 20 and 40. The experiments were conducted for ten Froude number (Fr) run ranging from 1.117 to 9.909 with 0.700<yc/h<3.00. The focus of research to investigate the relationship between relative energy losses in skimming flow performance against Froude number on various stepped. The effect of number of steps is evident when the relative energy loss increases with the number of steps. In addition, the relative energy loss of flow on pooled steps is dissipating more energy than flat steps.

scholarly journals The Effect of Inception Point on Dissipation Energy in Stepped Spillways Modeling

2019 ◽  
Vol 54 (3) ◽  
Author(s):  
Denik Sri Krisnayanti ◽  
Suhardjono ◽  
Very Dermawan ◽  
Djoko Legono
Keyword(s):  
Energy Loss ◽  
Relative Energy ◽  
Downstream Face ◽  
Stepped Spillway ◽  
Critical Depth ◽  
Roughness Factor ◽  
Flow Conditions ◽  
Dissipation Energy ◽  
Stepped Spillways ◽  
Inception Point

Stepped spillway is generally a modification on the downstream face of a standard ogee spillway. The steps increase significantly the rate of energy dissipation taking place along the chute and reduce the size of the need for a large energy dissipate at the toe of the spillway. In skimming flow conditions, the steps act as roughness factor which is great because most of the energy is lost to maintain horizontal vortices that develop beneath the pseudo bottom. This study aimed to investigate the effect of the inception point against the value of the relative energy loss on the stepped spillway in skimming flow regime. In this research, the models test of stepped spillway carried out with twelve configuration and variations of ratio (dc/h). The slope of stepped spillway (θ) is used 30˚ and 45˚, the number of steps (N) are 40 and 20, and two type of steps: flat steps and pooled steps. The critical depth to the height of steps (dc/h) is ranging from 0.700 < dc/h < 3.00 with the discharge per unit width 69.13 cm2/s < q < 707.65 cm2/s. The results showed that the relative energy loss can be analyzed to be a function of the inception points, the number of steps, and the slope of spillway, in the equation form of (ΔH/Hmax) = a (Li/ks)bNc(sin θ)d. The discharge which function of the Froude number and height of the step already include to the length of inception point parameters.

scholarly journals Numerical study of energy dissipation and block barriers in stepped spillways

2020 ◽  
Author(s):  
Mehdi Karami Moghadam ◽  
Ata Amini ◽  
Ehsan Karami Moghadam
Keyword(s):  
Energy Dissipation ◽  
Numerical Study ◽  
Flow Simulation ◽  
Step Length ◽  
Energy Dissipation Rate ◽  
Relative Energy ◽  
Stepped Spillway ◽  
Stepped Spillways ◽  
Using Data ◽  
Turbulent Models

Abstract In this research, the accuracy of the Flow-3D numerical model in the flow simulation in a stepped spillway was probed using data obtained from the physical model. In addition, the effects of block barriers on the energy dissipation rate were investigated. To adopt a proper turbulent model, Renormalization Group k-ε, RNG k-ε, and standard k-ε models were employed. Then, the Flow-3D was run in five discharges for nine spillways with the ratios of block length to step length (Lb/l) and block height to step height (Hb/h) as 0.3, 0.4, and 0.5. The results indicated that both turbulent models had almost similar outcomes though the run time of the RNG k-ε model was shorter. The blocks with a shorter length in low ratios of Hb/h and the lengthier blocks in high ratios of Hb/h undergo more relative energy dissipation relative to the no-block situation. For Hb/h = 0.3 and Lb/l equal to 0.3, 0.4, and 0.5, the relative energy dissipation climbed on average as 8.5, 6.5, and 4.5% respectively, compared with the no-block case. The most influence exerted on relative energy dissipation was obtained via the blocks with Hb/h = Lb/l equal to 0.3 and 0.5 with respective increases of 8.6 and 8.4%.

Spatial Variability of Physical Parameters and Processes in Two Field Soils

1991 ◽  
Vol 22 (5) ◽  
pp. 327-340 ◽  
Author(s):  
K. Høgh Jensen ◽  
J. C. Refsgaard
Keyword(s):  
Transport Model ◽  
Flow Direction ◽  
Measurement Data ◽  
Flow Simulation ◽  
Solute Concentration ◽  
Conclusive Evidence ◽  
Physical Parameters ◽  
Effective Parameters ◽  
The Mean ◽  
Tracer Experiments

A numerical analysis of solute transport in two spatially heterogeneous fields is carried out assuming that the fields are composed of ensembles of one-dimensional non-interacting soil columns, each column representing a possible soil profile in statistical terms. The basis for the analysis is the flow simulation described in Part II (Jensen and Refsgaard, this issue), which serves as input to a transport model based on the convection-dispersion equation. The simulations of the average and variation in solute concentration in planes perpendicular to the flow direction are compared to measurements obtained from tracer experiments carried out at the two fields. Due to the limited amount of measurement data, it is difficult to draw conclusive evidence of the simulations, but reliable simulations are obtained of the mean behaviour within the two fields. The concept of equivalent soil properties is also tested for the transport problem in heterogeneous soils. Based on effective parameters for the retention and hydraulic conductivity functions it is possible to predict the mean transport in the two experimental fields.

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