Dynamic wake development of a floating wind turbine in free pitch motion subjected to turbulent inflow generated with an active grid

2017 ◽  
Vol 112 ◽  
pp. 1-16 ◽  
Author(s):  
Stanislav Rockel ◽  
Joachim Peinke ◽  
Michael Hölling ◽  
Raúl Bayoán Cal
Keyword(s):  
Wind Turbine ◽  
Pitch Motion ◽  
Active Grid ◽  
Floating Wind Turbine ◽  
Turbulent Inflow

Wind shear effect induced by the platform pitch motion of a spar-type floating wind turbine

2019 ◽  
Vol 135 ◽  
pp. 1186-1199 ◽  
Author(s):  
Binrong Wen ◽  
Xinliang Tian ◽  
Qi Zhang ◽  
Xingjian Dong ◽  
Zhike Peng ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Shear ◽  
Shear Effect ◽  
Pitch Motion ◽  
Floating Wind Turbine

The unsteady aerodynamics of floating wind turbine under platform pitch motion

2018 ◽  
Vol 232 (8) ◽  
pp. 1019-1036 ◽  
Author(s):  
Xin Shen ◽  
Ping Hu ◽  
Jinge Chen ◽  
Xiaocheng Zhu ◽  
Zhaohui Du
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Degrees Of Freedom ◽  
Unsteady Aerodynamics ◽  
Aerodynamic Performance ◽  
Floating Platform ◽  
Pitch Motion ◽  
Floating Wind Turbine ◽  
Fixed Base ◽  
Turbine Rotors

The aerodynamic performance of floating platform wind turbines is much more complex than fixed-base wind turbines because of the flexibility of the floating platform. Due to the extra six degrees-of-freedom of the floating platform, the inflow of the wind turbine rotors is highly influenced by the motions of the floating platform. It is therefore of interest to study the unsteady aerodynamics of the wind turbine rotors involved with the interaction of the floating platform induced motions. In the present work, a lifting surface method with a free wake model is developed for analysis of the unsteady aerodynamics of wind turbines. The aerodynamic performance of the NREL 5 MW floating wind turbine under the prescribed floating platform pitch motion is studied. The unsteady aerodynamic loads, the transient of wind turbine states, and the instability of the wind turbine wakes are discussed in detail.

Wake to wake interaction of floating wind turbine models in free pitch motion: An eddy viscosity and mixing length approach

2016 ◽  
Vol 85 ◽  
pp. 666-676 ◽  
Author(s):  
Stanislav Rockel ◽  
Joachim Peinke ◽  
Michael Hölling ◽  
Raúl Bayoán Cal
Keyword(s):  
Wind Turbine ◽  
Eddy Viscosity ◽  
Mixing Length ◽  
Pitch Motion ◽  
Floating Wind Turbine ◽  
Wake Interaction

Nonlinear Pitch Decay Motion of a Floating Offshore Wind Turbine Structure

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
K. P. Thiagarajan ◽  
R. Urbina ◽  
W. Hsu
Keyword(s):  
Wind Turbine ◽  
Flow Speed ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Natural Period ◽  
Thrust Coefficient ◽  
Pitch Motion ◽  
Blade Element Theory ◽  
Floating Wind Turbine ◽  
Decay Tests

Model tests were conducted on three generic floating wind turbine systems in 2011 and reported in a series of papers at the 31st Ocean, Offshore, and Arctic Engineering Conference in 2012. These tests were conducted at the MARIN facility in The Netherlands, by a consortium of universities, government research organizations, and industry. As part of the testing program, decay tests in platform pitch were conducted with and without wind forcing. It was found that for spar and semisubmersible type structures, resonant pitch motion was damped due to wind in storm sea conditions. The nonlinear decay motion of a floating wind turbine platform is modeled using a one degree-of-freedom nonlinear oscillation equation about a mean offset angle. Attention is paid to the turbine thrust coefficient and its variability with respect to oncoming flow speed, which in turn is affected by the structure pitch motion. The equation of motion reveals that the mean offset position has an important role in the stiffness, damping, and consequently the natural period of pitch motion. Several important dimensionless parameters are introduced. The paper discusses a simple thrust model for an offshore wind turbine (OWT) based on rudiments of blade element theory. Using the simplified thrust coefficient formulation, the increase in platform pitch damping due to wind is formulated. Experimental data reported from prior tests described above show good agreement with the theoretical model.

Nonlinear Pitch Decay of a Floating Offshore Wind Turbine Structure

2013 ◽  
Author(s):  
K. P. Thiagarajan ◽  
R. Urbina ◽  
W. Hsu
Keyword(s):  
Wind Turbine ◽  
Flow Speed ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Natural Period ◽  
Thrust Coefficient ◽  
Pitch Motion ◽  
Blade Element Theory ◽  
Floating Wind Turbine ◽  
Decay Tests

Model tests were conducted on three generic floating wind turbine systems in 2011, and reported in a series of papers at OMAE 2012. These tests were conducted at the MARIN facility in the Netherlands, by a consortium of universities, government research organizations and industry. As part of the testing program, decay tests in platform pitch were conducted with and without wind. It was found that for spar and semi-submersible type structures, resonant pitch motion was damped due to wind in storm sea conditions. The nonlinear decay motion of a floating wind turbine platform is modeled using a one degree-of-freedom nonlinear oscillation equation about a mean offset angle. Attention is paid to the turbine thrust coefficient and its variability with respect to oncoming flow speed, which in turn is affected by the structure pitch motion. The equation of motion reveals that the mean offset position has an important role in the stiffness, damping and consequently the natural period of pitch motion. Several important dimensionless parameters are introduced. The paper discusses a simple thrust model for an offshore wind turbine based on rudiments of blade element theory. Using the simplified thrust coefficient formulation, the increase in platform pitch damping due to wind is formulated. Experimental data reported from prior tests described above show good agreement with the theoretical model.

scholarly journals Experimental Study on Influence of Pitch Motion on the Wake of a Floating Wind Turbine Model

Energies ◽  
2014 ◽  
Vol 7 (4) ◽  
pp. 1954-1985 ◽  
Author(s):  
Stanislav Rockel ◽  
Elizabeth Camp ◽  
Jonas Schmidt ◽  
Joachim Peinke ◽  
Raúl Cal ◽  
...  
Keyword(s):  
Experimental Study ◽  
Wind Turbine ◽  
Pitch Motion ◽  
Floating Wind Turbine ◽  
Turbine Model

Comparisons Between the Typical Wind Shear and the Wind Shear Induced by Platform Pitch Motion for an Offshore Floating Wind Turbine

2018 ◽  
Author(s):  
Binrong Wen ◽  
Qi Zhang ◽  
Sha Wei ◽  
Xinliang Tian ◽  
Xingjian Dong ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Shear ◽  
Vortex Method ◽  
Speed Ratio ◽  
Wind Speed Profile ◽  
Pitch Motion ◽  
Floating Wind Turbine ◽  
Advanced Control ◽  
Offshore Floating Wind Turbine

The pitch motion of the Offshore Floating Wind Turbine (OFWT) introduces additional wind speed to the rotor. The additional wind speed distributes linearly along the vertical altitude, which is called as the platform-pitch-induced wind shear effect in this paper. Comparisons between the typical wind shear and the platform-pitch-induced wind shear are conducted with the Free Vortex Method (FVM) for the NREL 5MW baseline wind turbine. It is found that the platform-pitch-induced wind shear is the results of the rotor rotating and platform pitching, and its wind speed profile is time-varying. At the designed point of tip speed ratio of 7, the averaged power output is reduced slightly under the typical wind shear while it is increased by 4% under the platform-pitch-induced wind shear. The aerodynamic loads of the OFWT under the platform pitch-induced wind shear experience much more considerable variations than the typical wind shear, which introduce severer fatigue damages to the OFWT components. For the sake of the safety of the OFWT, advanced control strategy and superior design should be developed to mitigate the platform pitch motion.

Selection of a leading edge noise prediction method for PNoise

2018 ◽  
pp. 214-223
Author(s):  
AM Faria ◽  
MM Pimenta ◽  
JY Saab Jr. ◽  
S Rodriguez
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Prediction Method ◽  
Leading Edge ◽  
Wind Farms ◽  
Broadband Noise ◽  
Turbulence Energy ◽  
Noise Prediction ◽  
Migration Routes ◽  
Turbulent Inflow

Wind energy expansion is worldwide followed by various limitations, i.e. land availability, the NIMBY (not in my backyard) attitude, interference on birds migration routes and so on. This undeniable expansion is pushing wind farms near populated areas throughout the years, where noise regulation is more stringent. That demands solutions for the wind turbine (WT) industry, in order to produce quieter WT units. Focusing in the subject of airfoil noise prediction, it can help the assessment and design of quieter wind turbine blades. Considering the airfoil noise as a composition of many sound sources, and in light of the fact that the main noise production mechanisms are the airfoil self-noise and the turbulent inflow (TI) noise, this work is concentrated on the latter. TI noise is classified as an interaction noise, produced by the turbulent inflow, incident on the airfoil leading edge (LE). Theoretical and semi-empirical methods for the TI noise prediction are already available, based on Amiet’s broadband noise theory. Analysis of many TI noise prediction methods is provided by this work in the literature review, as well as the turbulence energy spectrum modeling. This is then followed by comparison of the most reliable TI noise methodologies, qualitatively and quantitatively, with the error estimation, compared to the Ffowcs Williams-Hawkings solution for computational aeroacoustics. Basis for integration of airfoil inflow noise prediction into a wind turbine noise prediction code is the final goal of this work.

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