scholarly journals Numerical and physical model study of a vertical slot fishway

2014 ◽  
Vol 62 (2) ◽  
pp. 150-159 ◽  
Author(s):  
Martin Bombač ◽  
Gorazd Novak ◽  
Primož Rodič ◽  
Matjaž Četina
Keyword(s):  
Numerical Model ◽  
Eddy Viscosity ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Maximum Velocity ◽  
Energy Dissipation Rate ◽  
Model Study ◽  
Vertical Slot ◽  
Vertical Slot Fishway ◽  
Turbulent Models

Abstract This paper presents the results of an experimental and numerical study of a vertical slot fishway (VSF). A 2-D depth-averaged shallow water numerical model PCFLOW2D coupled with three different turbulent models (constant eddy viscosity, Smagorinsky and k - ε) was used. A detailed analysis of numerical parameters needed for a correct simulation of the phenomenon was carried out. Besides the velocity field, attention was paid to important hydraulic parameters such as maximum velocity in the slot region and energy dissipation rate ε in order to evaluate the performance of VSF. A scaled physical hydraulic model was built to ensure reliable experimental data for the validation of the numerical model. Simulations of variant configurations of VSF showed that even small changes in geometry can produce more fishfriendly flow characteristics in pools. The present study indicates that the PCFLOW2D program is an appropriate tool to meet the main demands of the VSF design.

scholarly journals A Numerical Study of Fluid Flow in a Vertical Slot Fishway with the Smoothed Particle Hydrodynamics Method

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1928 ◽  
Author(s):  
Gorazd Novak ◽  
Angelantonio Tafuni ◽  
José M. Domínguez ◽  
Matjaž Četina ◽  
Dušan Žagar
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Numerical Study ◽  
Free Surface Flows ◽  
Open Boundary ◽  
Doppler Velocity ◽  
Vertical Slot ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Smoothed Particle Hydrodynamics Method ◽  
Vertical Slot Fishway

Fishways have a great ecological importance as they help mitigate the interruptions of fish migration routes. In the present work, the novel DualSPHysics v4.4 solver, based on the smoothed particle hydrodynamics method (SPH), has been applied to perform three-dimensional (3-D) simulations of water flow in a vertical slot fishway (VSF). The model has been successfully calibrated against published field data of flow velocities that were measured with acoustic Doppler velocity probes. A state-of-the-art algorithm for the treatment of open boundary conditions using buffer layers has been applied to accurately reproduce discharges, water elevations, and average velocity profiles (longitudinal and transverse velocities) within the observed pool of the VSF. Results herein indicate that DualSPHysics can be an accurate tool for modeling turbulent subcritical free surface flows similar to those that occur in VSF. A novel relation between the number of fluid particles and the artificial viscosity coefficient has been formulated with a simple logarithmic fit.

scholarly journals NUMERICAL STUDY OF NEARSHORE HYDRODYNAMICS UNDER STORM WAVE CONDITIONS IN HUJEONG BEACH, EAST COAST OF KOREA

2018 ◽  
pp. 67
Author(s):  
Yeon S. Chang ◽  
Jong Dae Do ◽  
Kyungmo Ahn ◽  
Jae-Youll Jin
Keyword(s):  
Numerical Model ◽  
East Coast ◽  
Surf Zone ◽  
Numerical Study ◽  
Navier Stokes ◽  
Model Study ◽  
Suspended Sediment Concentrations ◽  
Storm Wave ◽  
Wave Conditions ◽  
The Republic

In this study, we present the results of numerical model study to simulate the hydrodynamic conditions observed in Hujeong Beach in the east coast of the Republic of Kore from December, 2016 to January, 2017 during which several extratropical cyclones hit the area causing extreme wave conditions. Three acoustic instrumentation systems were moored from the coast to a location outside the surf zone where the water depth was ~8m to measure waves, currents and suspended sediment concentrations. For the numerical model, we employed the CADMAS-SURF Raynolds-Averaged Navier-Stokes (RANS) model to generate the wave conditions over the region of the field experiment.

scholarly journals A Numerical Study on the Flow Characteristics and Flow Uniformity of Vanadium Redox Flow Battery Flow Frame

2020 ◽  
Vol 10 (23) ◽  
pp. 8427
Author(s):  
Jun-Yong Park ◽  
Deok-Young Sohn ◽  
Yun-Ho Choi
Keyword(s):  
Pressure Drop ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Maximum Velocity ◽  
Flow Channel ◽  
Vanadium Redox Flow Battery ◽  
Redox Flow Battery ◽  
Flow Uniformity ◽  
Flow Battery ◽  
Vanadium Redox

As the demand for electrical energy increases worldwide, the amounts of harmful gases in the atmosphere, such as carbon dioxide released by burning fossil fuel, are continuously increasing. As a result, the interest in renewable energy resources has been growing. However, renewable energies have fluctuating output characteristics according to local conditions such as the natural environment and geographical characteristics, which is a major factor deteriorating output quality. Recently, energy storage systems (ESSs) have been actively studied as a solution to this problem. A redox flow battery (RFB) is a system in which an active material dissolved in an electrolyte is oxidized/reduced to charge/discharge. A RFB mainly consists of an electrolyte tank, which determines the capacity, and a cell stack, which determines the output. As these components can be independently controlled, a RFB provides the advantages of a large capacity and a long lifespan. In this study, a new flow channel was designed to maximize the reaction area and reduce the pump loss to improve RFB performance. Computational fluid dynamics (CFD) and visualization experiments were used to analyze the internal flow characteristics of vanadium redox flow battery (VRFB). Additionally, we used the variability range coefficient and maximum velocity deviation to check if the flow discharged to the electrode was uniform. In the conventional flow frame, the flow discharged to the electrode has a non-uniformity distribution in the left and right, due to the S-shaped path of the inlet channel. In addition, it was confirmed that the outlet area into the electrode was reduced to 50%, resulting in a high pressure drop. To address this problem, we proposed a design that simplified the flow channel, which significantly improved flow uniformity parameters. The maximum velocity deviations for the existing and new flow channels were 11.89% and 54.16%, respectively. In addition, in the entire flow frame for the new flow channel, the pressure drop decreased by 44% as compared with the existing flow channel.

Swimming ability of juvenile Australian bass, Macquaria novemaculeata (Steindachner), and juvenile barramundi, LAtes calcarifer (Bloch), in an experimental vertical-slot fishway

1992 ◽  
Vol 43 (4) ◽  
pp. 823 ◽  
Author(s):  
M Mallen-Cooper
Keyword(s):  
Juvenile Fish ◽  
Fork Length ◽  
Maximum Velocity ◽  
Water Velocity ◽  
Swimming Ability ◽  
Probit Regression ◽  
Vertical Slot ◽  
In The Wild ◽  
Vertical Slot Fishway ◽  
Coefficient Of Discharge

Australian bass, Macquaria novemaculeata, and barramundi, Lates calcarlfer, are catadromous fish that spawn in estuaries and the juveniles migrate upstream into fresh water. Lowland fishways in the range of these species therefore need to accommodate these juvenile fish. The swimming abilities of three size classes (fork length (LCF) + s.d.: 40 * 3 mm, 64 + 5 mm and 93 + 8 mm) of juvenile Australian bass and one size class (43 4 mm total length) of juvenile barramundi were tested in an experimental vertical-slot fishway. Water velocity was calculated from the head loss in water level between adjacent pools in the fishway, using a coefficient of discharge (Cd) of 1.0. Both species readily negotiated the fishway at low water velocities, indicating that the fish were in a migratory mode and that these fish could use the vertical-slot design of the fishway. The sigmoidal decrease in this ability with increasing water velocity was described by a probit regression. The NV95 value (maximum negotiable water velocity for 95% of the sample) is suggested as the suitable maximum-velocity criterion for vertical-slot fishways for these fishes. The NV95 values were 0.66 m s-1 for 43-mm barramundi, 1.02 m s-1 for 40-mm bass, 1.40 m s-1 for 64-mm bass and 1.84 m s-1 for 93-mm bass. The NV95 for barramundi is probably an underestimate of their swimming ability in the wild because the water temperature was low for this species. Up to 20% of the 93-mm bass died at test velocities greater than 2.0 m s-1, but there were no mortalities of other fish during or immediately following a trial. The results indicate that water velocity in fishways for juvenile bass and barramundi should not exceed 1.4 m s-1 in a cell size of 1.5 m length and 1.0 m width. The relative swimming speeds (body lengths per second) of bass in the fishway are higher than other estimates of burst swimming speeds of juvenile fish obtained from studies in flumes. This indicates that data from the latter type of study should not be used to determine water velocities for fishways.

Numerical study on flow characteristics of rotor pumps including cavitation

2014 ◽  
Vol 229 (14) ◽  
pp. 2626-2638 ◽  
Author(s):  
Yingyuan Liu ◽  
Leqin Wang ◽  
Zuchao Zhu
Keyword(s):  
Numerical Model ◽  
Mass Flow ◽  
Volume Fraction ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Two Dimensional ◽  
Flow Rates ◽  
Factors Affecting ◽  
Remarkable Effect ◽  
Mass Flow Rates

This work is purposed to study the flow characteristics of rotor pumps including cavitation. First, a simplified two-dimensional numerical model is developed and computing strategies of the numerical analysis for cavitation are set up, including the selection of cavitation model and its parameters. Second, the reliability and accuracy of the two-dimensional numerical model are verified by experimental results. Then, several factors affecting the cavitation are discussed, including the rotational speeds, pressure differences, clearance sizes, and inlet pressures. For different rotational speeds and pressure differences, the mass flow rates with cavitation are a little larger than that without cavitation, but the amplitudes of the mass flow rates with cavitation are much larger than that without cavitation. Meanwhile, the volume fraction of the water vapor increases with the increasing speeds and the decreasing pressure differences. However, compared with the influence of rotational speeds, the influence of the pressure differences on the vapor contents is relatively smaller. Regarding the clearance size, the smaller the clearance size is, the stronger the cavitation will be. Furthermore, the clearance size between two rotors has a larger effect on the cavitation than that between rotor and pump case. For inlet pressure, it has a little effect on the mass flow rates when cavitation is not considered, but it presents a remarkable effect for the model with cavitation. In addition, the peaks of the volume fractions of vapor and the mass flow rates generally offset backward with the decreasing inlet pressures.

scholarly journals ONE- AND THREE-DIMENSIONAL MODELING OF A VERTICAL-SLOT FISHWAY

2017 ◽  
pp. 99-107 ◽  
Author(s):  
Camila Yuri Lira Umeda ◽  
Guilherme de Lima ◽  
Johannes Gérson Janzen ◽  
Marcio Ricardo Salla
Keyword(s):  
Energy Dissipation ◽  
Dissipation Rate ◽  
Numerical Models ◽  
Three Dimensional ◽  
Energy Dissipation Rate ◽  
Flow Speed ◽  
Design Parameters ◽  
Vertical Slot ◽  
Hydraulic Design ◽  
Vertical Slot Fishway

This paper compares the use of one-dimensional (1-D) and three-dimensional (3-D) numerical models to simulate the flow of a vertical-slot fishway. Prior to their application, the models are validated by comparing the predicted data with experimental data from a physical model. Then the numerical models are applied to calculate four critical hydraulic design parameters of vertical-slot fishways, i.e., flow speed, water depth, turbulent kinetic energy, and energy dissipation rate. Furthermore, the authors developed rating curves for flow rate and energy dissipation rate in terms of flow depth using data from the 1-D model. These curves have great utility for the operation of the vertical-slot fishway studied. The results indicate that 1-D modeling can be a useful tool for preliminary conservative design arrangements of vertical-slot fishways, and that 3-D modeling can be a useful tool to enable accurate representation of the critical hydraulic design parameters and selection of the most appropriate design.

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%.

Numerical Investigation of the Effects of the Cross-Shore and Groyne-Wall Slopes on Flow Pattern Around an Impermeable Groyne

2008 ◽  
Author(s):  
R. Ghaldarbandi ◽  
H. Hakimzadeh
Keyword(s):  
Numerical Model ◽  
Flow Pattern ◽  
Eddy Viscosity ◽  
Numerical Test ◽  
Maximum Velocity ◽  
Shear Stresses ◽  
Computational Domain ◽  
Reynolds Stresses ◽  
Cross Sectional ◽  
The Cross

The groynes which are typical of shore protective structures can provide several aims. Although these structures may partly help to shoreline protection, they would also create some major problems in adjacent regions. Therefore the real performance of these structures needs to be considered carefully before going to construction. In this research, the effects of the cross shore and groyne wall slopes on flow pattern around an impermeable groyne were considered using a three-dimensional numerical CFD model (i.e., FLUENT). The widely accepted eddy viscosity concept and k-ε turbulence model were used to evaluate the Reynolds stresses and eddy viscosity coefficients, respectively. The finite volume method used in the software makes attractive flexibility to use any shape of grids to cover the cross and structural slopes in the computational domain. The model was first applied to a vertical groyne on a flat bed and the numerical model results were compared with experimental data. The model results of this numerical test showed a very good agreement with the corresponding experimental measurements, in terms of water elevation and velocity magnitudes. The model was then applied to a series of structures with different lateral slopes on various cross sectional bed slope. It was found that the flow pattern around the groyne was not changed significantly when the slopes of the structure and bed were slightly changed. The numerical model results, however, showed that by increasing the cross shore slope in any case of the lateral slope of the structure, the magnitude of the maximum velocity was decreased. The bed shear stresses were also decreased when the cross shore slope was increased. Moreover, these values were further decreased when the groyne-wall slope was reduced.

scholarly journals Numerical Investigation of Hydraulics in a Vertical Slot Fishway with Upgraded Configurations

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2711
Author(s):  
Mohammad Ahmadi ◽  
Amir Ghaderi ◽  
Hossein MohammadNezhad ◽  
Alban Kuriqi ◽  
Silvia Di Francesco
Keyword(s):  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Large Diameter ◽  
Maximum Velocity ◽  
Cost Effective ◽  
Hydraulic Structures ◽  
The Sustainable Development ◽  
Vertical Slot ◽  
Vertical Slot Fishway ◽  
Design Cost

The implementation of vertical slot fishway (VSF) has been demonstrated to be an effective mitigation measure to alleviate extensive river fragmentation by artificial hydraulic structures such as weirs and dams. However, non-suitable flow velocity and turbulent kinetic energy significantly affect fish swimming behavior and, as a result, hinder such facilities’ performance. Therefore, this study’s main objective is to propose a new configuration of VSF that can allow the passage of different fish species under frequent variations of flow discharge. To achieve that objective several novel configurations of VSF were numerically investigated using the FLOW-3D® model. Namely, five variants of angles between baffles, four different pool widths, and another upgraded version of VSF by introducing cylindrical elements positioned after the opening behind the baffles were tested. Results show that smaller angles between baffles increase the Vmax and decrease the maximum turbulent kinetic energy (TKEmax); the opposite result was obtained when increasing angles between baffles. Namely, the Vmax was increased up to 17.9% for α = 0° and decreased up to 20.37% for α = 37°; in contrast, TKEmax decreased up to −20% for α = 0° and increased up to 26.5% for α = 37°. Narrowing the pool width increased the Vmax linearly; nevertheless, it did not significantly affect the TKEmax as the maximum difference was only +3.5%. Using cylinders with a large diameter decreased the Vmax and increased TKEmax; in contrast, using cylinders with smaller diameters further reduced the Vmax velocity inside the pool while increasing the TKEmax. However, in the case of cylinders, the dimension of the recirculation depended on the configuration and arrangement of the cylinder within the pool. Overall, the maximum velocity was reached at near 77% of the water depth in all cases. Finally, solution-oriented findings resulted from this study would help water engineers to design cost-effective VSF fishways to support the sustainable development of hydraulic structures while preserving aquatic biodiversity.

Sign in / Sign up

Export Citation Format

Share Document