Resolution of tower shadow models for downwind mounted rotors and its effects on the blade fatigue

Reiso, Marit; Muskulus, Michael

doi:10.1088/1742-6596/555/1/012084

Cited by 4 publications

(2 citation statements)

References 3 publications

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“…23 The longitudinal resolution was 25 Hz. The simulation time was 150 s, instead of the usual 600 s (recommended in the relevant standards, with typical lateral resolutions of 32 Â 32 points), to be within standard file size limits for these detailed wind field representations.…”

Section: E Wind Filementioning

confidence: 99%

The simultaneous effect of a fairing tower and increased blade flexibility on a downwind mounted rotor

Reiso

Muskulus

2013

Journal of Renewable and Sustainable Energy

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This is a parametric study on how blade and tower loads for a prototypical downwind offshore wind turbine are affected as the tower geometry and blade properties are changed. Downwind turbines have the potential to reduce the cost of energy, as blades can be more flexible and lighter, but the tower shadow induces additional structural vibrations. In order to reduce the latter, a fairing around the tower has been introduced. The length of the fairing is varied, adjusting the rotor overhang accordingly. Additionally, the blade weight and stiffness are adjusted. The blade and tower fatigue loads are, thereby, significantly decreased. In the first case, a maximum reduction of 8% and 28% (for the blade root bending and tower bottom moment, respectively) was achieved, compared to a downwind version of the National Renewable Energy Laboratory (NREL) 5 MW reference wind turbine on a monopile tower. Using softer and lighter blades resulted in loads even lower than for the conventional upwind rotor of the NREL turbine, up to 5% and 13% less for the blade and tower fatigue loads, respectively. The increased overhang increased the mean tower bending moments, suggesting that an optimal downwind turbine needs to be designed with a compromise between these fatigue and ultimate loads. The power production stayed approximately the same as that of a conventional wind turbine or was slightly higher. V C 2013 AIP Publishing LLC.

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Section: E Wind Filementioning

confidence: 99%

The simultaneous effect of a fairing tower and increased blade flexibility on a downwind mounted rotor

Reiso

Muskulus

2013

Journal of Renewable and Sustainable Energy

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“…This could cause structural vibration and aerodynamic noise and reduce the fatigue life and output power. Regarding aerodynamic research on downwind rotors, Reiso and Muskulus [ 7 ] analyzed the two-dimensional flow field behind cylindrical and truss towers. They concluded that the primary contributors to blade fatigue load were average velocity deficit and turbulence.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Aerodynamic Characteristics of Downwind Bionic Tower Wind Turbine

Yang,

Sun,

Yang

et al. 2024

Biomimetics

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The vibrissae of harbor seals exhibit a distinct three-dimensional structure compared to circular cylinders, resulting in a wave-shaped configuration that effectively reduces drag and suppresses vortex shedding in the wake. However, this unique cylinder design has not yet been applied to wind power technologies. Therefore, this study applies this concept to the design of downwind wind turbines and employs wind tunnel testing to compare the wake flow characteristics of a single-cylinder model while also investigating the output power and wake performance of the model wind turbine. Herein, we demonstrate that in the single-cylinder test, the bionic case shows reduced turbulence intensity in its wake compared to that observed with the circular cylinder case. The difference in the energy distribution in the frequency domain behind the cylinder was mainly manifested in the near-wake region. Moreover, our findings indicate that differences in power coefficient are predominantly noticeable with high tip speed ratios. Furthermore, as output power increases, this bionic cylindrical structure induces greater velocity deficit and higher turbulence intensity behind the rotor. These results provide valuable insights for optimizing aerodynamic designs of wind turbines towards achieving enhanced efficiency for converting wind energy.

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Turbulent Inflow Models

Ehrich¹

2020

Handbook of Wind Energy Aerodynamics

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Resolution of tower shadow models for downwind mounted rotors and its effects on the blade fatigue

Cited by 4 publications

References 3 publications

The simultaneous effect of a fairing tower and increased blade flexibility on a downwind mounted rotor

The simultaneous effect of a fairing tower and increased blade flexibility on a downwind mounted rotor

Experimental Study on Aerodynamic Characteristics of Downwind Bionic Tower Wind Turbine

Turbulent Inflow Models

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