Hans Bernhoff
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View article: Cost and Efficiency analysis of the Secondary electric machine in a CRAFT wind turbine
Cost and Efficiency analysis of the Secondary electric machine in a CRAFT wind turbine Open
Floating offshore wind turbines are ideal for deeper waters, providing access to stronger and more stable winds. The Counter-Rotating Axis Floating Tilting (CRAFT) turbine features a unique design with two counter-rotating turbines on a ti…
View article: Material aspects of wooden towers for offshore wind turbines
Material aspects of wooden towers for offshore wind turbines Open
Possible new innovative materials for Counter Rotating Axis Floating Tilted Turbines are studied and discussed. The 40 MW version of the Counter Rotating Axis Floating Tilted Turbine (CRAFTT) will reach as far as 80 m below sea surface and…
View article: Vortex filament method 3D analysis of design parameters for counter-rotating axis floating tilted turbine
Vortex filament method 3D analysis of design parameters for counter-rotating axis floating tilted turbine Open
The Counter-Rotating Axis Floating Tilted turbine (CRAFT) is a new design for floating off-shore wind power, which utilizes a low center of gravity and allows the tower to tilt to mitigate costs for platforming. In this study, 3D simulatio…
View article: Design and Simulation study of 40 MW PM Generator for the CRAFT
Design and Simulation study of 40 MW PM Generator for the CRAFT Open
Design studies of two counter rotating permanent magnet (PM) synchronous generators have been performed. The two 40 MW generators have been designed and compared for the Counter Rotating Axis Floating Turbine (CRAFT) with different air-gap…
View article: Comparison of Three-Dimensional Numerical Methods for Modeling of Strut Effect on the Performance of a Vertical Axis Wind Turbine
Comparison of Three-Dimensional Numerical Methods for Modeling of Strut Effect on the Performance of a Vertical Axis Wind Turbine Open
This paper compares three different numerical models to evaluate their accuracy for predicting the performance of an H-rotor vertical-axis wind turbine (VAWT) considering the influence of struts. The strut of VAWTs is one factor that makes…
View article: A numerical study of strut and tower influence on the performance of vertical axis wind turbines using computational fluid dynamics simulation
A numerical study of strut and tower influence on the performance of vertical axis wind turbines using computational fluid dynamics simulation Open
This paper presents the influence of the strut and the tower on the aerodynamic force of the blade for the vertical axis wind turbine (VAWT). It has been known that struts degrade the performance of VAWTs due to the inherent drag losses. I…
View article: Aeroacoustic noise prediction of a vertical axis wind turbine using large eddy simulation
Aeroacoustic noise prediction of a vertical axis wind turbine using large eddy simulation Open
This study investigates the numerical prediction for the aerodynamic noise of the vertical axis wind turbine using large eddy simulation and the acoustic analogy. Low noise designs are required especially in residential areas, and sound le…
View article: The Radio Neutrino Observatory Greenland (RNO-G)
The Radio Neutrino Observatory Greenland (RNO-G) Open
The Radio Neutrino Observatory Greenland (RNO-G) is scheduled for deployment in the summerof 2021. It will target the detection of astrophysical and cosmogenic neutrinos above 10 PeV. With 35 autonomous stations, it will be the largest imp…
View article: Numerical prediction of noise generated from airfoil in stall using LES and acoustic analogy
Numerical prediction of noise generated from airfoil in stall using LES and acoustic analogy Open
This article presents the aerodynamic noise prediction of a NACA 0012 airfoil in stall region using Large Eddy Simulation and the acoustic analogy. While most numerical studies focus on noise for an airfoil at a low angle of attack, predic…
View article: Direction Reconstruction for the Radio Neutrino Observatory Greenland (RNO-G)
Direction Reconstruction for the Radio Neutrino Observatory Greenland (RNO-G) Open
The Radio Neutrino Observatory Greenland (RNO-G) is planned to be the first large-scale implementation of the in-ice radio detection technique. It targets astrophysical as well as cosmogenic neutrinos with energies above 10 PeV. The deep c…
View article: Hardware Development for the Radio Neutrino Observatory in Greenland (RNO-G)
Hardware Development for the Radio Neutrino Observatory in Greenland (RNO-G) Open
The Radio Neutrino Observatory in Greenland (RNO-G) is designed to make the first observations of ultra-high energy neutrinos at energies above 10 PeV, playing a unique role in multi-messenger astrophysics as the world's largest in-ice Ask…
View article: Energy reconstruction with the Radio Neutrino Observatory Greenland (RNO-G)
Energy reconstruction with the Radio Neutrino Observatory Greenland (RNO-G) Open
Starting in summer 2021, the Radio Neutrino Observatory Greenland (RNO-G) will attempt to\nachieve the first detection of neutrinos with energies at the EeV scale. We present a method to\nreconstruct the energy of neutrino-induced particle…
View article: Capabilities of ARIANNA: Neutrino Pointing Resolution and Implications for Future Ultra-high Energy Neutrino Astronomy
Capabilities of ARIANNA: Neutrino Pointing Resolution and Implications for Future Ultra-high Energy Neutrino Astronomy Open
A radio-frequency polarization measurement by the ARIANNA surface station was performed using a residual hole from the South Pole Ice Core (SPICEcore) Project. Radio pulses were emitted from a transmitter located down to 1.7 km below the s…
View article: Polarization Reconstruction of Cosmic Rays with the ARIANNA Neutrino Radio Detector
Polarization Reconstruction of Cosmic Rays with the ARIANNA Neutrino Radio Detector Open
The ARIANNA detector is designed to detect neutrinos of energies above 10 PeV. Due to the similarities in generated radio signals, cosmic rays are often used as test beams for neutrino detectors. Some ARIANNA detector stations are equipped…
View article: Science case and detector concept for ARIANNA high energy neutrino telescope at Moore's Bay, Antarctica
Science case and detector concept for ARIANNA high energy neutrino telescope at Moore's Bay, Antarctica Open
The ARIANNA neutrino detector, located at sea-level on the Ross Ice Shelf, Antarctica, consists of 200 autonomous and independent detector stations separated by 1 kilometer in a uniform triangular mesh, and serves to inform the planning of…
View article: A novel trigger based on neural networks for radio neutrino detectors
A novel trigger based on neural networks for radio neutrino detectors Open
The ARIANNA experiment is a proposed Askaryan detector designed to record radio signals induced by neutrino interactions in the Antarctic ice. Because of the low neutrino flux at high energies, the physics output is limited by statistics. …
View article: TAROGE-M: Radio Observatory on Antarctic High Mountain for Detecting Near-Horizon Ultra-High Energy Air Showers
TAROGE-M: Radio Observatory on Antarctic High Mountain for Detecting Near-Horizon Ultra-High Energy Air Showers Open
The TAROGE-M observatory is an autonomous antenna array on the top of Mt.~Melbourne ($\sim2700$ m altitude) in Antarctica, designed to detect radio pulses from ultra-high energy (over $10^{17}$ eV) air showers coming from near-horizon dire…
View article: Development of an in-situ calibration device of firn properties for Askaryan neutrino detectors
Development of an in-situ calibration device of firn properties for Askaryan neutrino detectors Open
High energy neutrinos ($E>10^{17}$ eV) are detected cost-efficiently via the Askaryan effect in ice, where a particle cascade induced by the neutrino interaction produces coherent radio emission that can be picked up by antennas installed …
View article: Student-centered learning in an engineering course with project-integrated laboratory experiment
Student-centered learning in an engineering course with project-integrated laboratory experiment Open
In this paper we discuss and present results from the pedagogical development of an advancedlevel undergraduate electrical engineering course at Uppsala University, where a new laboratory experiment was implemented. The implementation of t…
View article: White Paper: ARIANNA-200 high energy neutrino telescope
White Paper: ARIANNA-200 high energy neutrino telescope Open
The proposed ARIANNA-200 neutrino detector, located at sea-level on the Ross Ice Shelf, Antarctica, consists of 200 autonomous and independent detector stations separated by 1 kilometer in a uniform triangular mesh, and serves as a pathfin…
View article: Numerical Study of a Novel Concept for Manufacturing Savonius Turbines with Twisted Blades
Numerical Study of a Novel Concept for Manufacturing Savonius Turbines with Twisted Blades Open
This work presents a numerical study of the aerodynamic performance and the resulting flow field of two novel Savonius wind turbines with twisted blades. The novelty relies on the blade manufacturing process which is characterized by a ‘tw…
View article: Neutrino vertex reconstruction with in-ice radio detectors using surface reflections and implications for the neutrino energy resolution
Neutrino vertex reconstruction with in-ice radio detectors using surface reflections and implications for the neutrino energy resolution Open
Ultra high energy neutrinos (Eν > 1016.5eV) are efficiently measured via radio signals following a neutrino interaction in ice. An antenna placed1Script O(15 m) below the ice surface will measure two signals for the vast majority of events…
View article: Eddy currents in a passive magnetic axial thrust bearing for a flywheel energy storage system
Eddy currents in a passive magnetic axial thrust bearing for a flywheel energy storage system Open
Two types of passive magnetic lift bearings were evaluated in terms of thrust force and eddy current losses. The first type of bearings were based on two sets of segmented Halbach arrays mounted in repulsive mode, and the second type was b…
View article: Reluctance Machine for a Hollow Cylinder Flywheel
Reluctance Machine for a Hollow Cylinder Flywheel Open
A hollow cylinder flywheel rotor with a novel outer rotor switched reluctance machine (SRM) mounted on the interior rim is presented, with measurements, numerical analysis and analytical models. Practical experiences from the construction …