Blar i NTNU Open på forfatter "Hearst, Robert Jason"
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Aerodynamics of an airfoil subjected to icing
Kyrkjebø, Magnus (Master thesis, 2018)Wind turbines located in cold climate face several issues due to ice accretion. These include power losses, mechanical failures and changes in the aerodynamic behaviour. Particle image velocimetry measurements have been ... -
Characterizing porous disk wakes in different turbulent inflow conditions with higher-order statistics
Vinnes, Magnus Kyrkjebø; Neunaber, Ingrid; Lykke, Hauk-Morten Heimlund; Hearst, Robert Jason (Peer reviewed; Journal article, 2023)The wakes of a uniform and a non-uniform porous disk exposed to two different turbulent flows are investigated experimentally. The disks are representative of static wind turbine models found in literature. Six wake profiles ... -
Characterizing the surface texture of a dense suspension undergoing dynamic jamming
Rømcke, Olav; Peters, Ivo R.; Hearst, Robert Jason (Peer reviewed; Journal article, 2021)Measurements of the surface velocity and surface texture of a freely propagating shear jamming front in a dense suspension are compared. The velocity fields are captured with particle image velocimetry (PIV), while the ... -
Development of an aqueous lignin mixture thermophysical model for hydrothermal liquefaction applications using uncertainty quantification tools
Simões Nunes, Ângelo Dinis; Sierra-Pallaras, José; Tran, Quang Khanh; Hearst, Robert Jason (Peer reviewed; Journal article, 2022)A thermophysical model is developed that can predict the properties of two lignin mixtures, black liquor and lignosulfonates, up to 50% mass fractions, at hydrothermal conditions. An uncertainty quantification framework ... -
The effect of inlet turbulence on the quiescent core of turbulent channel flow
Asadi, Masoud; Kamruzzaman, Md; Hearst, Robert Jason (Peer reviewed; Journal article, 2022)The impact of inlet turbulence on the structure of turbulent channel flow is investigated using particle image velocimetry. Streamwise–wall-normal plane measurements are performed in a channel, where different turbulence ... -
Error Sources in Wave-Based Remote Sensing and Free-Surface Synthetic Schlieren
Weichert, Stefan (Doctoral theses at NTNU;2024:244, Doctoral thesis, 2024)Physical processes at and under the water surface of oceans play a key role in the Earth’s climate. For the models that are used to make predictions of temperature, gas contents, humidity, etc., we rely on data from ... -
Exploring Turbulence - Turbulence Interactions: Impacts of Incoming Turbulence on Wall-Bounded Flows
Asadi, Masoud (Doctoral theses at NTNU;2024:16, Doctoral thesis, 2024)Turbulent wall-bounded flows form a cornerstone of modern fluid mechanics research and are ubiquitous in diverse natural and industrial settings. In practical scenarios, turbulent wall-bounded flows are commonly exposed ... -
The far wake of porous disks and a model wind turbine: Similarities and differences assessed by hot-wire anemometry
Vinnes, Magnus Kyrkjebø; Gambuzza, Stefano; Ganapathisubramani, Bharathram; Hearst, Robert Jason (Peer reviewed; Journal article, 2022)The wakes of two different porous disks have been evaluated experimentally. Such disks are commonly used as physical actuator disk analogs for wind turbines. One disk is made of a uniform wire mesh, while the other has a ... -
The flow in the induction and entrance regions of lab-scale wind farms
Vinnes, Magnus Kyrkjebø; Worth, Nicholas Alexander; Segalini, Antonio; Hearst, Robert Jason (Peer reviewed; Journal article, 2023)With the increasing demand for wind energy, it is important to be able to understand and predict the available wind resources. To that end, the present wind tunnel study addresses the flow in the induction and entrance ... -
Getting jammed in all directions: Dynamic shear jamming around a cylinder towed through a dense suspension
Rømcke, Olav; Peters, Ivo R.; Hearst, Robert Jason (Peer reviewed; Journal article, 2021)Experimental results of towing a cylinder through a dense suspension of cornstarch and sucrose-water are presented. Focus is placed on the jamming fronts that exist in such systems. The literature has concentrated on the ... -
Influence of incoming turbulence and shear on the flow field and performance of a lab-scale roof-mounted vertical axis wind turbine
Jooss, Yannick; Hearst, Robert Jason; Bracchi, Tania Kalogiannidis (Peer reviewed; Journal article, 2023)Flow conditions in an urban environment are complex, featuring varying levels of turbulence intensity and shear. The influence of these flow characteristics on the performance of a roof-mounted vertical axis wind turbine ... -
Influence of position and wind direction on the performance of a roof mounted vertical axis wind turbine
Jooss, Yannick; Rønning, Eivind Berg; Hearst, Robert Jason; Bracchi, Tania (Peer reviewed; Journal article, 2022)The ideal position for a roof mounted wind turbine is investigated experimentally in a wind tunnel. The set-up consists of two cube-shaped buildings. A Savonius (drag driven) vertical axis wind turbine is placed on one of ... -
Performance and wake measurements of a Savonius wind turbine
Jessen, Marius Stette; Aliferis, Alexander Dahl (Master thesis, 2018)In this study, the performance, drag and wake characteristics of a vertical axis Savonius wind turbine are investigated experimentally. The turbine is drag driven and has a helical configuration, making the top rotated 180 ... -
Signifikant Reduksjon i Luftmotstanden på en Sylinder ved bruk av Striper og Tekstiler
Skeide, Arne Kilvik (Master thesis, 2019)Effekten av striper og små-skala overflateruhet på luftmotstanden og virvelavløsningen til en sirkulær sylinder, har blitt undersøkt. En sylinder ble dekket av et 'tekstil' bestående av halvsirkulære striper liggende ... -
Spatial development of a turbulent boundary layer subjected to freestream turbulence
Jooss, Yannick; Li, Leon; Bracchi, Tania; Hearst, Robert Jason (Peer reviewed; Journal article, 2021)The spatial development of a turbulent boundary layer (TBL) subjected to freestream turbulence (FST) is investigated experimentally in a water channel for friction Reynolds numbers up to Reτ=5060. Four different FST ... -
Structure of turbulent channel flow subjected to simultaneous inlet turbulence and localized injection
Asadi, Masoud; Kamruzzaman, Md; Hearst, Robert Jason (Journal article; Peer reviewed, 2022)The combined effects of inlet turbulence and localized injection on turbulent channel flow are investigated experimentally in an air channel. A porous plate was used to locally inject air streams at the bottom wall of the ... -
The effect of turbulence and blockage orientation on the near-field of porous disks
Lykke, Hauk-Morten Heimlund (Master thesis, 2019)Vindtunnel-eksperimenter har blitt gjennomført med en solid disk og to ulike porøse disker med identisk soliditet plassert i strømninger med to forskjellige turbulens-intensiteter med et Reynoldstall på Re =110 000. En av ... -
Uniform-momentum zones in a turbulent boundary layer subjected to freestream turbulence
Hearst, Robert Jason; de Silva, Charitha; Dogan, Eda; Ganapathisubramani, Bharathram (Peer reviewed; Journal article, 2021)The instantaneous structure of a turbulent boundary layer that has developed beneath freestream turbulence (FST) was investigated with planar particle image velocimetry. Measurements were performed in the streamwise–wall-normal ... -
Volumetric visualization of vanishing vortices in wind turbine wakes
Hillestad, Johannes Næsset; Yadala Venkata, Srikar; Neunaber, Ingrid Johanne; Li, Leon; Hearst, Robert Jason; Worth, Nicholas Alexander (Journal article; Peer reviewed, 2024)Volumetric velocimetry is used to investigate the evolution of tip vortices in the wake of a model wind turbine. The power spectral density of streamwise velocity fluctuations is estimated at several downstream locations, ...