Ismail Albayrak


Last Name

Albayrak

First Name

Ismail

ORCID

0000-0002-4613-6726

Organisational unit

03820 - Boes, Robert / Boes, Robert

Filters

2011 - 2019932020 - 202667
Reset filters

Search Results

Publications 1 - 10 of 160
  • Development of Low-Voltage Electrified Fish Guidance Racks for Safe Downstream Fish Migration
    Item type: Conference Paper
    Moldenhauer-Roth, Anita; Selz, Oliver M.; Unterberger, Felix; et al. (2022)
    Proceedings 39th IAHR World Congress
    Downstream moving fish may have to pass through turbines or spillways of run-of-river hydropower plants (HPPs), which can result in life-threatening injuries. Fish guidance structures such as a vertical curved-bar rack (CBR) or horizontal bar rack (HBR) in combination with a bypass can safely guide different fish species around HPPs, thereby providing a safe downstream fish passage route. HBRs are a physical barrier to the passage of parts of the fish fauna due to narrow bar spacings and partly induce behavioral guidance, while the CBR creates turbulent structures in front of the rack, inducing a behavioral guidance and protection effect. HBRs are mainly applied at small- to medium-scale HPPs because of their velocity limitation and narrow bar spacing causing clogging problems. Combining an HBR with a low voltage electric field (e-HBR) may permit the use of larger bar spacings while maintaining high protection efficiencies. A CBR with a 50 mm bar spacing showed high protection rates for certain cyprinid species in laboratory experiments. However, European eel (Anguilla anguilla) were less receptive to hydraulic cues by the CBR resulting in low guidance efficiency. Electrifying the CBR (e-CBR) may improve the protection efficiency for eel. In the present study, the electric field generated at an e-HBR and e-CBR was numerically simulated. Subsequently, tests of e-HBR and e- BR were conducted with European eel in a large laboratory flume at ETH Zurich. Both e-HBR and e-CBR improved protection and guidance compared to the non – electrified racks for European eel. Guidance and protection efficiencies were not affected by the approach flow velocity varying from 0.15 m/s to 0.6 m/s.
  • An experimental investigation on fish guidance structures with horizontal bars
    Item type: Journal Article
    Albayrak, Ismail; Maager, Fiona; Boes, Robert (2020)
    Journal of Hydraulic Research
  • Research projects on reservoir sedimentation and sediment routing at VAW, ETH Zurich, Switzerland
    Item type: Journal Article
    Albayrak, Ismail; Felix, David; Schmocker, Lukas; et al. (2018)
    Hydrolink
  • Analysis And Optimization of Hydraulic Characteristics at Fish Guidance Structures Using CFD
    Item type: Conference Paper
    Leuch, Claudia; Beck, Claudia; Albayrak, Ismail; et al. (2022)
    Proceedings 39th IAHR World Congress
    Mechanical behavioural fish guidance racks (FGR) with vertical bars are a promising technical solution for the safe downstream movement of fish at run-of-river hydropower plants (HPP) and water intakes. They do not pose a physical barrier to most fish but rather create flow patterns that deter fish from passing the bar rack and guide them towards a bypass system. Current knowledge of flow parameters that induce this avoidance behaviour is limited. Furthermore, FGR may impair the energy production and operation of HPP as they generate additional head losses and affect the turbine admission flow through deflection of the current. In order to provide a widely applicable and robust solution, a balance between effective fish guidance and minimal hydraulic losses needs to be found. In this study, a computational fluid dynamics (CFD) approach is used to efficiently test and compare different bar shapes and their impact on the flow field both upstream and downstream of the FGR. The results show that the use of hydro-dynamically shaped bars significantly improves the hydraulic performance of the rack. Furthermore, the study proves that CFD modelling is a valuable tool for this kind of analysis as parameters can easily be adapted and the results can be obtained in high spatial and temporal resolution.
  • Hydro-abrasion processes and modelling at hydraulic structures and steep bedrock rivers: 2. Hydro-abrasion model development and application
    Item type: Journal Article
    Demiral, Dila; Albayrak, Ismail; Turowski, Jens M.; et al. (2026)
    Journal of Hydro-environment Research
    Hydro-abrasion is a process of wear resulting from the mechanical stress exerted by impacting particles in the flow on a riverbed or banks or on the invert of hydraulic structures. Hydro-abrasion models represent the mechanics of invert abrasion by bed load particles and allow to predict hydro-abrasion rates. The present study deals with the enhancement of the existing mechanistic saltation hydro-abrasion model by incorporating new equations for particle velocity, hop length, an exponential cover effect term, and two additional important terms accounting for particle hardness and saltation probability, respectively. We particularly focus on the effects of particle and bed lining material hardness, bed cover, and low aspect ratio on hydro-abrasion, which were not holistically investigated in previous studies. The non-dimensional hydro-abrasion coefficient ​kv​ (also known as the rock resistance coefficient) in the enhanced model was calibrated using both experimental laboratory data and field measurements obtained from three Swiss Sediment Bypass Tunnels as part of our research project. A constant value of kv = 4.8 ± 2.2 × 10^4 was obtained for a range of different materials with less scattering compared to the coefficients reported in previous studies. The enhanced model demonstrated a good performance when validated with independent data from laboratory and field studies, indicating that the laboratory results can be upscaled to prototype conditions.
  • The Attractiveness of Fishways and Bypass Facilities
    Item type: Book Chapter
    Peter, Armin; Schoelzel, Nils; Wilmsmeier, Lisa; et al. (2022)
    Novel Developments for Sustainable Hydropower
  • A new system for 3D fish-tracking
    Item type: Report
    Detert, Martin; Albayrak, Ismail; Boes, Robert (2019)
    Large-scale laboratory investigations with live-fish, i.e. so-called ethohydraulic tests, are used to understand interactions between the hydraulics of fish protection technologies and fish behaviour and hence to improve the current design of fish passages or develop new technologies. For such laboratory applications, a 3D fish-tracking system was developed. The system consists of vertically submerged cameras synchronously recording to a PC periphery system and a MATLAB-based 3D tracking software to determine fish locations in the flow. The software tracks several fish in 3D. Swimming path-time diagrams give a distinct big picture of the fish movements, which help to identify fish preferred and disliked regions in so-called heat maps. These diagrams are based on detailed 3D fish tracks. This report presents camera set-up, details of the algorithm, an exemplary application of the system and its limitations. Although the 3D fish-tracking system is developed for laboratory applications, it may also be used in the field to monitor fish movements or to count fish at fish passage facilities after slight adaptations of field conditions to the system.
  • Fishfriendly Innovative Technologies for hydropower (FIThydro)
    Item type: Other Conference Item
    Meister, Julian; Beck, Claudia; Fuchs, Helge; et al. (2018)
  • Massnahmen zur Gewährleistung eines schonenden Fischabstiegs
    Item type: Journal Article
    Kriewitz, Carl Robert; Boes, Robert; Albayrak, Ismail (2013)
    Aqua Viva
  • Sediment transport in high-speed flows over a fixed bed: 1. Particle dynamics
    Item type: Journal Article
    Auel, Christian; Albayrak, Ismail; Sumi, Tetsuya; et al. (2017)
    Earth Surface Processes and Landforms
Publications 1 - 10 of 160