Browsing NTNU Open by Author "Sætran, Lars Roar"
Now showing items 1-20 of 30
-
A Detached-Eddy-Simulation study: Proper-Orthogonal-Decomposition of the wake flow behind a model wind turbine
Göing, Jan; Bartl, Jan Michael Simon; Mühle, Franz Volker; Sætran, Lars Roar; Thamsen, Paul Uwe (Journal article; Peer reviewed, 2018)In times of intense renewable energy development, the planning of wind farms and the improvement of their total efficiency has become a major field of research. A precise analysis of the velocity deficit, fluctuation load ... -
Aerodynamic Optimisation of Airfoils and Winglets for Wind Turbine Application
Hansen, Thomas (Doctoral theses at NTNU;2017:263, Doctoral thesis, 2017)The presented thesis summarises work on applying evolutionary optimisation algorithms for the design of airfoils and winglets for wind turbine application. This approach is more computationally expensive than using traditional ... -
Blind test comparison of the performance and wake flow between two in-line wind turbines exposed to different turbulent inflow conditions
Bartl, Jan Michael Simon; Sætran, Lars Roar (Journal article; Peer reviewed, 2017)This is a summary of the results of the fourth blind test workshop that was held in Trondheim in October 2015. Herein, computational predictions on the performance of two in-line model wind turbines as well as the mean and ... -
Blind test comparison on the wake behind a yawed wind turbine
Mühle, Franz Volker; Schottler, Jannik; Bartl, Jan Michael Simon; Futrzynski, Romain; Evans, Steve; Bernini, Luca; Schito, Paolo; Draper, Martín; Guggeri, Andrés; Kleusberg, Elektra; Henningson, Dan S.; Hölling, Michael; Peinke, Joachim; Adaramola, Muyiwa S.; Sætran, Lars Roar (Journal article; Peer reviewed, 2018)This article summarizes the results of the “Blind test 5” workshop, which was held in Visby, Sweden, in May 2017. This study compares the numerical predictions of the wake flow behind a model wind turbine operated in yaw ... -
Comparing Abnormalities in Onshore and Offshore Vertical Wind Profiles
Møller, Mathias (Master thesis, 2019)Kunnskap om den vertikale utviklingen av vindprofilen er essensielt for design og drift av vindturbiner. Denne kunnskapen trengs ikke kun for ekstrapolering av vindhastigheten til turbinens høyde, men er også nødvendig ... -
Comparing abnormalities in onshore and offshore vertical wind profiles
Møller, Mathias; Domagalski, Piotr; Sætran, Lars Roar (Peer reviewed; Journal article, 2020)Understanding the vertical wind profile is paramount for design and operation of wind turbines. It is needed not only for extrapolation of the wind velocity to hub height but also for structural load calculations, to name ... -
Computational fluid dynamics simulations of a Formula Student race car - Effects predicted by the modelling of a steady state cornering vehicle
Sagmo, Kristian Forfot (Master thesis, 2016)In this thesis work an investigation of the aerodynamics of a Fomula Student race car was conducted. The work focused on a computational fuid dynamics evaluation of the aerodynamic effects predicted for the car moving ... -
Cross-sectional wake measurements of actuator disks.
Karlsen, Benjamin (Master thesis, 2019)Eit tversnitt normalt på straumninga i vakane til to ikkje-roterande vindturbinmodellar har blitt målt ved x = 4D nedstraums. Ved å bruke ein 4-hols Cobra probe har vanlege aksiale straumningsmålingar blitt utvida til å ... -
Experimental and numerical icing penalties of an S826 airfoil at low Reynolds numbers
Hann, Richard; Hearst, R. Jason; Sætran, Lars Roar; Bracchi, Tania (Peer reviewed; Journal article, 2020)Most icing research focuses on the high Reynolds number regime and manned aviation. Information on icing at low Reynolds numbers, as it is encountered by wind turbines and unmanned aerial vehicles, is less available, and ... -
Experimental study on power curtailment of three in-line turbines
Bartl, Jan Michael Simon; Ostovan, Yasar; Uzol, Oguz; Sætran, Lars Roar (Journal article; Peer reviewed, 2017)A dataset of wind tunnel power and wake flow measurements on a setup of three aligned model wind turbines is presented. The power outputs of the three turbines are in good agreement with measurements from a full-scale wind ... -
An experimental study on the effects of winglets on the tip vortex interaction in the near wake of a model wind turbine
Bartl, Jan; Mühle, Franz Volker; Hansen, Thomas; Adaramola, Muyiwa S.; Sætran, Lars Roar (Peer reviewed; Journal article, 2020)An experimental study of the near wake up to four rotor diameters behind a model wind turbine rotor with two different wing tip configurations is performed. A straight‐cut wing tip and a downstream‐facing winglet shape are ... -
Experimental testing of wind turbine wake control methods
Bartl, Jan (Doctoral theses at NTNU;2018:107, Doctoral thesis, 2018)In the light of the growing world-wide wind energy production, the optimization of wind farms has become an increasingly important field of research. Herein, the aerodynamic interactions between the single turbines through ... -
Experimental validation of analytical wake and downstream turbine performance modelling
Polster, Felix; Bartl, Jan Michael Simon; Mühle, Franz Volker; Thamsen, Paul Uwe; Sætran, Lars Roar (Journal article; Peer reviewed, 2018)Wake effects in wind farms can cause significant power losses. In order to reduce these losses layout and control optimization can be applied. For this purpose, simple and fast prediction tools for the wake flow are needed. ... -
Experiments in the wind turbine far wake for the evaluation of an analytical wake model
Garcia, Luis; Vatn, Mari; Mühle, Franz Volker; Sætran, Lars Roar (Journal article; Peer reviewed, 2017)Nowadays, not only the size of single wind turbines but also the size of wind farms is increasing. Understanding the interaction between the turbines and especially the wakes formed behind them are getting more important ... -
Investigating the influence of tip vortices on deflection phenomena in the near wake of a wind turbine model
Kuhn, Wolf Ludwig (Master thesis, 2019)In order to optimize wind farm control, wake deflection strategies through yaw misalignment have recently been widely discussed. For this purpose, the characteristics of the mean and turbulent wake flow behind a yawed ... -
Lidars for Wind Tunnels - an IRPWind Joint Experiment Project
Sjöholm, Mikael; Vignaroli, Andrea; Angelou, Nikolas; Nielsen, Morten Busk; Mann, Jakob; Mikkelsen, Torben; Bolstad, Hans Christian; Merz, Karl Otto; Sætran, Lars Roar; Mühle, Franz Volker; Tiihonen, Mikko; Lethomäki, Ville (Journal article; Peer reviewed, 2017)Measurement campaigns with continuous-wave Doppler Lidars (Light detection and ranging) developed at DTU Wind Energy in Denmark were performed in two very different wind tunnels. Firstly, a measurement campaign in a small ... -
Modelling of Aerodynamic Drag in Alpine Skiing
Elfmark, Ola (Master thesis, 2017)Most of the breaking force in the speed disciplines in alpine skiing is caused by the aerodynamic drag, and a better knowledge of the drag force is therefore desirable to gain time in races. In this study a complete database ... -
Near-field response of an axisymmetric jet to transverse acoustic forcing
Hanssen-Bauer, Øyvind Waage (Doctoral theses at NTNU;2020:142, Doctoral thesis, 2020)The overall aim of this thesis was to investigate a transversely forced, round air-jet, with focus on the coherent vortex structures formed in the near-field of the jet. Increased knowledge about the interaction between ... -
Performance and wake development behind two in-line and offset model wind turbines - "Blind test" experiments and calculations
Sætran, Lars Roar; Krogstad, Per-Åge; Adaramola, Muyiwa S. (Journal article; Peer reviewed, 2014)This is a report on data presented at the ”Blind test 3” Workshop organized jointly by Nowitech and Norcowe in Bergen, December 2013. A number of research groups were invited to predict the performances and the wake ... -
Performance of the NREL S826 airfoil at low to moderate Reynolds numbers — A reference experiment for CFD models
Bartl, Jan Michael Simon; Sagmo, Kristian Forfot; Bracchi, Tania; Sætran, Lars Roar (Journal article; Peer reviewed, 2019)Lift, drag and surface pressure measurements are performed on a wing section of the NREL S826 wind turbine airfoil at eight Reynolds numbers ranging from 0:5_105 to 6:0_105. Alongside with the measurements two types of ...