Blar i Bergen Open Research Archive på forfatter "Kral, Stephan Thomas"
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Atmospheric Drivers of Wind Turbine Blade Leading Edge Erosion: Review and Recommendations for Future Research
Pryor, Sara C.; Barthelmie, Rebecca Jane; Cadence, Jeremy; Dellwik, Ebba; Hasager, Charlotte Bay; Kral, Stephan Thomas; Reuder, Joachim; Rodgers, Marianne; Veraart, Marijn (Journal article; Peer reviewed, 2022)Leading edge erosion (LEE) of wind turbine blades causes decreased aerodynamic performance leading to lower power production and revenue and increased operations and maintenance costs. LEE is caused primarily by materials ... -
Experimental Characterization of Propeller-Induced Flow (PIF) below a Multi-Rotor UAV
Flem, Alexander Arvid; Ghirardelli, Mauro; Kral, Stephan Thomas; Cheynet, Etienne; Kristensen, Tor Olav; Reuder, Joachim (Journal article; Peer reviewed, 2024-02-20)The availability of multi-rotor UAVs with lifting capacities of several kilograms allows for a new paradigm in atmospheric measurement techniques, i.e., the integration of research-grade sonic anemometers for airborne ... -
Flow Structure around a Multicopter Drone: A Computational Fluid Dynamics Analysis for Sensor Placement Considerations
Ghirardelli, Mauro; Kral, Stephan Thomas; Müller, Nicolas Carlo; Hann, Richard; Cheynet, Etienne; Reuder, Joachim (Journal article; Peer reviewed, 2023)This study presents a computational fluid dynamics (CFD) based approach to determine the optimal positioning for an atmospheric turbulence sensor on a rotary-wing uncrewed aerial vehicle (UAV) with X8 configuration. The ... -
Rain erosion atlas for wind turbine blades based on ERA5 and NORA3 for Scandinavia
Hannesdóttir, Ásta; Kral, Stephan Thomas; Reuder, Joachim; Hasager, Charlotte Bay (Journal article; Peer reviewed, 2024)Leading edge erosion on wind turbine blades is a common issue, particularly for wind turbines placed in regions characterized by high wind speeds and precipitation. This study presents the development of a rain erosion ... -
Rotary-wing drone-induced flow - Comparison of simulations with lidar measurements
Jin, Liqin; Ghirardelli, Mauro; Manne, Jakob; Sjöholm, Mikael; Kral, Stephan Thomas; Reuder, Joachim (Journal article; Peer reviewed, 2024)Ultrasonic anemometers mounted on rotary-wing drones have the potential to provide a cost-efficient alternative to the classical meteorological mast-mounted counterpart for atmospheric boundary layer research. However, the ... -
The stable atmospheric boundary layer over snow-covered sea ice: Model evaluation with fine-scale ISOBAR18 observations
Lorenz, Torge; Mayer, Stephanie; Kral, Stephan Thomas; Suomi, Irene; Steeneveld, Gert Jan; Holtslag, Albert A.M. (Journal article; Peer reviewed, 2022)A realistic representation of the stable atmospheric boundary layer in numerical weather prediction (NWP) and climate models is still a challenge. We study the evolution of a stable boundary layer over snow-covered sea ice ... -
Unmanned Aircraft Get Together: The LAPSE-RATE Campaign
de Boer, Gijs; Diehl, Constantin; Jacob, Jamey; Houston, Adam; Smith, Suzanne W.; Chilson, Phillip; Schmale, David; Intrieri, Janet; Pinto, J; Elston, Jack; Brus, David; Kemppinen, Osku; Clark, A; Lawrence, D.; Bailey, Sean C.C.; Sama, Michael P.; Frazier, Amy; Crick, Christopher; Natalie, Victoria; Pillar-Little, Elizabeth A.; Klein, Petra; Waugh, Sean; Lundquist, Julie K.; Barbieri, Lindsay; Kral, Stephan Thomas; Jensen, A; Dixon, Cory; Borenstein, Steve; Hesselius, Daniel; Human, Kathleen; Hall, P; Argrow, Brian; Thornberry, T; Wright, R; Kelly, James T. (Journal article; Peer reviewed, 2020)Members of the international community developing unmanned aircraft for atmospheric research conducted a highly successful coordinated flight week in Colorado during the summer of 2018 to collect measurements, develop ...