scholarly journals A Parametric Approach for Determining Fishway Attraction Flow at Hydropower Dams

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 743
Author(s):  
Patrick Heneka ◽  
Markus Zinkhahn ◽  
Cornelia Schütz ◽  
Roman B. Weichert
Keyword(s):  
Input Data ◽  
Design Criterion ◽  
Hydraulic Parameters ◽  
Parametric Approach ◽  
Temporal Complexity ◽  
Hydropower Plants ◽  
Hydropower Dams ◽  
Migration Corridor ◽  
Zone Characteristic ◽  
Good Agreement

High discharges at hydropower plants (HPP) may mask fishway attraction flows and, thereby, prevent fishes from locating and using fishways critical for their access to upstream spawning and rearing habitats. Existing methods for determining attraction flows are either based on simple guidelines (e.g., a proportion of HPP discharge) that cannot address the spatial and temporal complexity of tailrace flow patterns or complicated studies (e.g., combinations of detailed hydraulic and biological investigations) that are expensive and time-consuming. To bridge this gap, we present a new, intermediate approach to reliably determine attraction flows for technical fishways at small to medium-sized waterways (mean annual flow up to 400 m3/s). Fundamental to our approach is a design criterion that the attraction flow should maintain its integrity as it propagates downstream from the fishway entrance to beyond the highly turbulent zone characteristic of HPP tailraces to create a discernable migration corridor connecting the fishway entrance to the downstream river. To implement this criterion, we describe a set of equations to calculate the width of the entrance and the corresponding attraction discharge. Input data are usually easy to obtain and include geometrical and hydraulic parameters describing the target HPP and its tailrace. To confirm our approach, we compare model results to four sites at German waterways where the design of attraction flow was obtained by detailed experimental and numerical methods. The comparison shows good agreement supporting our approach as a useful, intermediate alternative for determining attraction flows that bridges the gap between simple guidelines and detailed hydraulic and biological investigations.

scholarly journals Hydropower Development and Fishways: A Need for Connectivity in Rivers of the Upper Paraná Basin

2019 ◽  
Vol 11 (13) ◽  
pp. 3749 ◽  
Author(s):  
Sergio Makrakis ◽  
Ana P. S. Bertão ◽  
Jhony F. M. Silva ◽  
Maristela C. Makrakis ◽  
Fco. Javier Sanz-Ronda ◽  
...  
Keyword(s):  
Scientific Literature ◽  
Structural Connectivity ◽  
Paraná River ◽  
South American ◽  
Hydroelectric Dams ◽  
Migratory Fish ◽  
Parana River ◽  
Hydropower Plants ◽  
Hydropower Dams ◽  
Upper Paraná River

South American rivers have become intensely affected by the construction of hydroelectric dams that block the river’s connectivity for migratory fish species. In order to mitigate the problems caused by dams and to reestablish connections between habitats, fishways are implemented. Fishways are structures that aid fish in overcoming obstacles and help preserve migratory, reproductive, and feeding routes. This study performed an inventory of all hydropower plants—present and future—in the Upper Paraná River, with the objective of identifying fishways unknown to scientific literature, as well as the task of mapping them. By doing so, the current situation of structural connectivity via fishways in the Upper Paraná River Basin was described. Overall, 389 dams along 209 rivers were identified; of these, only 9% (35 dams) have fishways. In addition, an alarming explosion of future medium-sized hydropower plants was observed, with an expectation of an almost 500% increase in relation to those existing. This data reveals a trend of reduction of free-flowing river stretches, which are crucial habitats for Neotropical potamodromous species, and point to a deficiency in the structural connectivity of existing hydropower dams. Furthermore, if the implementations of these expected constructions are associated with limited connectivity as a result of the absence of fishways, the management of fisheries and their resources in the Upper Paraná River may become unsustainable.

scholarly journals Turbulence generation from a stochastic wavelet model

2018 ◽  
Vol 474 (2217) ◽  
pp. 20180093
Author(s):  
Y. Du ◽  
G. Lin
Keyword(s):  
Input Data ◽  
Computation Cost ◽  
Fourier Methods ◽  
Numerical Examples ◽  
Scale Reduction ◽  
Inhomogeneous Turbulence ◽  
Comparable Accuracy ◽  
Turbulence Generation ◽  
Theoretical Results ◽  
Good Agreement

This research presents a new turbulence generation method based on stochastic wavelets and tests various properties of the generated turbulence field in both the homogeneous and inhomogeneous cases. Numerical results indicate that turbulence fields can be generated with much smaller bases in comparison to synthetic Fourier methods while maintaining comparable accuracy. Adaptive generation of inhomogeneous turbulence is achieved by a scale reduction algorithm, which greatly reduces the computation cost and practically introduces no error. The generating formula issued in this research could be adjusted to generate fully inhomogeneous and anisotropic turbulence with given RANS data under divergence-free constraint, which was not achieved previously in similar research. Numerical examples shows that the generated homogeneous and inhomogeneous turbulence are in good agreement with the input data and theoretical results.

The Study of Deepwater Drilling Parameters Optimization

2013 ◽  
Vol 275-277 ◽  
pp. 554-557
Author(s):  
Yu Jia Zhai ◽  
Zhi Ming Wang ◽  
Quan Zhang ◽  
Qing Chun Gao
Keyword(s):  
Optimization Method ◽  
Parameters Optimization ◽  
Hydraulic Parameters ◽  
Deepwater Drilling ◽  
Drilling Parameters ◽  
Good Agreement

Calculation and optimization of hydraulic parameters remains one of major challenges when planning and drilling deepwater wells. Based on traditional drilling theory and the characteristics of deepwater drilling, the particularity of deepwater drilling hydraulic parameters design is analyzed. According to the different features of the riser segment, inclined segment and horizon segment, the method for calculating the optimum displacement is proposed in segmental way. Besides, an applicable optimization method is presented for designing deepwater drilling parameters. The predicted value exhibits good agreement with measured value in drilling field, and it has practically guiding significance to deepwater drilling hydraulic parameters design.

Dynamic and Steady-State Analysis of an Auto-Regulator in a Flow Divider and/or Combiner Valve

1992 ◽  
Vol 114 (2) ◽  
pp. 306-314 ◽  
Author(s):  
M. Fedoroff ◽  
R. T. Burton ◽  
G. J. Schoenau ◽  
Y. Zhang
Keyword(s):  
Complex Model ◽  
Design Criterion ◽  
Loading Conditions ◽  
Stability Studies ◽  
The Past ◽  
Flow Divider ◽  
Wide Range ◽  
Power Bond Graph ◽  
Linearized Model ◽  
Good Agreement

Flow divider and/or combiner valves are hydraulic components which are used to divide and/or combine flow in a predetermined ratio independent of loading conditions. Over the past years the authors have successfully designed valves which can divide and/or combine flow with an error of less than 3 percent for all loading conditions. More recently, a valve which can be used to divide and combine flow for a wide range of flow requirements and still maintain an error of less than 3 percent has been developed and has been labeled an “auto-regulated high precision flow divider/combiner valve”. The heart of the auto-regulated valve is the autoregulator itself. In this paper, the operation of the regulator is discussed and design criterion for acceptable performance presented. A linearized model is developed from which a number of valve parameters are established. A more complex model using the Power Bond Graph technique is presented, and transient responses to different flow inputs are compared to experimental data. The model and experimental responses were in good agreement; hence, it was concluded that the model could be used with confidence in future stability studies.

scholarly journals Total Column Water Vapour Retrieval from S-5P/TROPOMI in the Visible Blue Spectral Range

2020 ◽  
Author(s):  
Christian Borger ◽  
Steffen Beirle ◽  
Steffen Dörner ◽  
Holger Sihler ◽  
Thomas Wagner
Keyword(s):  
Water Vapour ◽  
Spectral Range ◽  
Input Data ◽  
Reference Data ◽  
Boreal Summer ◽  
Data Sets ◽  
Clear Sky ◽  
Sky Conditions ◽  
Total Column ◽  
Good Agreement

Abstract. Total column water vapour has been retrieved from TROPOMI measurements in the visible blue spectral range and compared to a variety of different reference data sets for clear-sky conditions during boreal summer and winter. The retrieval consists of the common two-step DOAS approach: first the spectral analysis is performed within a linearized scheme and then the retrieved slant column densities are converted to vertical columns using an iterative scheme for the water vapour a priori profile shape which is based on an empirical parameterization of the water vapour scale height. Moreover, a modified albedo map was used combining the OMI LER albedo and scaled MODIS albedo map. The use of the alternative albedo is especially important over regions with very low albedo and high probability of clouds like the Amazon region. The errors of the TCWV retrieval have been theoretically estimated considering the contribution of a variety of different uncertainty sources. For observations during clear-sky conditions, over ocean surface, and at low solar zenith angles the error typically is around values of 10–20 % and during cloudy-sky conditions, over land surface, and at high solar zenith angles it reaches values around 20–50 %. In the framework of a validation study the retrieval demonstrates that it can well capture the global water vapour distribution: the retrieved H2O VCDs show very good agreement to the reference data sets over ocean for boreal summer and winter whereby the modified albedo map substantially improves the retrieval's consistency to the reference data sets in particular over tropical landmasses. However over land the retrieval underestimates the VCD by about 10 %, particularly during summertime. Our investigations show that this underestimation is likely caused by uncertainties within the surface albedo and the cloud input data: Low level clouds cause an underestimation but for mid to high level clouds good agreement is found. In addition, our investigations indicate that these biases can probably be further reduced by the use of updated cloud input data. The TCWV retrieval can be easily applied to further satellite sensors (e.g. GOME-2 or OMI) for creating uniform measurement data sets on longterm which is particularly interesting for climate and trend studies of water vapour.

scholarly journals Upstream fishway performance by Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) spawners at complex hydropower dams — is prior experience a success criterion?

2020 ◽  
pp. 1-11
Author(s):  
Anna Hagelin ◽  
Jon Museth ◽  
Larry Greenberg ◽  
Morten Kraabøl ◽  
Olle Calles ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Prior Experience ◽  
Fish Analysis ◽  
Atlantic Salmon Salmo Salar ◽  
Hydropower Plants ◽  
Hydropower Dams ◽  
Brown Trout Salmo Trutta

Passage of hydropower plants by upstream-migrating salmonid spawners is associated with reduced migration success, and the need for knowledge of fish behavior downstream of dams is widely recognized. In this study, we examined fishway passage of landlocked Atlantic salmon (Salmo salar) in River Klarälven, Sweden, and brown trout (Salmo trutta) in River Gudbrandslågen, Norway, and the influence of prior experience on passage success in 2012 and 2013. Fishway trap efficiency varied from 18% to 88% and was influenced by river discharge. Most salmon (81%) entered the fishway trap on days without spill, and salmon moved from the turbine area to the spill zone when there was spill, with small individuals showing a stronger reaction than large fish. Analysis of fish with and without prior trap experience showed that a higher percentage of the “naïve” fish (70% of salmon and 43% of the trout) entered the fishway traps than the “experienced” ones (25% of the salmon and 15% of the trout). Delays for fish that entered the trap ranged from 3 to 70 days for salmon and 2 to 47 days for trout.

Estimation of the Geometric Parameters of a Front Double Wishbone Suspension Based on Geometry Formulation

2015 ◽  
Author(s):  
R. C. Silva ◽  
M. A. A. Nunes ◽  
A. B. S. Oliveira ◽  
G. O. Andrade
Keyword(s):  
Automotive Industry ◽  
Input Data ◽  
Simulation Software ◽  
Geometric Parameters ◽  
Vehicle Suspension ◽  
Cartesian Coordinates ◽  
Analytical Formulae ◽  
Suspension Geometry ◽  
The Cost ◽  
Good Agreement

Vehicle suspension stands out as an important subsystem, which allows vertical compliance to the wheels following an uneven road; keeps the proper steer and camber attitudes, resist roll of the chassis and provides comfort for passengers. The suspension subsystem needs to comply with stability, handling and optimum steering based on an appropriate suspension geometry. Nowadays, the use of simulation software in automotive design has increased. However, the cost and complexity of such software can make them unavailable to those working in the domain, especially the young designers working in vehicle’s student competition (Baja SAE®). Thus, this paper aims to propose a methodology for assessing a frontal Double Wishbone suspension, which is based on a set of analytical equations implemented computationally at Matlab®. The formulae are developed considering simple concepts of algebra, trigonometry and geometry. The input data are the Cartesian coordinates (x, y, z) of predefined points, which are obtained from the CAD design and the bound/rebound travel. The main results are the simple analytical formulae, for the most important suspension’s geometric parameters: caster, camber and toe angles. These analytical results are validated with MSC ADAMS®, particularly its add-on specialized for the automotive industry ADAMS/Car®, showing good agreement.

scholarly journals Fish behavior and fish guidance at hydropower intake screens for fish downstream passage

2018 ◽  
Vol 40 ◽  
pp. 03041 ◽  
Author(s):  
Franz Geiger ◽  
Mathilde Cuchet ◽  
Peter Rutschmann
Keyword(s):  
Large Scale ◽  
Fish Behavior ◽  
Small Fish ◽  
Hydraulic Parameters ◽  
Field Observations ◽  
Fish Behaviour ◽  
Hydropower Plants ◽  
Hydraulic Design ◽  
Passage Efficiency ◽  
Fish Protection

Fish behaviour investigations under controlled laboratory conditions but nature like environment were conducted to clarify the efficiency of inclined and horizontal screen planes for fish protection and fish downstream passage at hydropower plants concerning different potamodromous species and various sizes. The dependency on the underlying geometric and hydraulic parameters was investigated and comprehensive models were deduced to describe these relations. Adequate geometric and hydraulic design could achieve high levels of fish protection and downstream passage efficiency, even for small fish, weak swimmers and riverbed/bottom oriented species. The results imply good transferability and accordance with field observations at large scale facilities and can provide valuable information for facility design.

On the propagation of Lamb Waves in Viscoelastic Composites for SHM Applications

2007 ◽  
Vol 347 ◽  
pp. 543-548 ◽  
Author(s):  
Mircea Calomfirescu ◽  
Axel S. Herrmann
Keyword(s):  
Stiffness Matrix ◽  
Input Data ◽  
Wave Attenuation ◽  
Lamb Waves ◽  
Matrix Coefficients ◽  
Viscoelastic Composites ◽  
Dispersion And Attenuation ◽  
Experimental Group ◽  
Group Velocities ◽  
Good Agreement

This paper presents a theoretical model for anisotropic wave attenuation in composites. The model has been implemented in a software called FIBREWAVE in order to predict dispersion and attenuation of A0 Lamb wave modes. The required input data are the complex stiffness matrix coefficients of the unidirectional plies of the composites, which have been measured by an immersion technique. Good agreement has been observed between predicted and experimental group velocities and wave attenuations.

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