scholarly journals Wind Turbine Design Optimization Under Environmental Uncertainty

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Marco Caboni ◽  
M. Sergio Campobasso ◽  
Edmondo Minisci
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Design Optimization ◽  
Rotor Design ◽  
Cost Of Energy ◽  
Mean Wind Speed ◽  
Significant Performance ◽  
The Mean ◽  
Wind Distribution ◽  
Turbine Design

Wind turbine design optimization is typically performed considering a given wind distribution. However, turbines so designed often end up being used at sites characterized by different wind distributions, resulting in significant performance penalties. This paper presents a probabilistic integrated multidisciplinary approach to the design optimization of multimegawatt wind turbines accounting for the stochastic variability of the mean wind speed. The presented technology is applied to the design of a 5 MW rotor for use at sites of wind power class from 3 to 7, where the mean wind speed at 50 m above the ground ranges from 6.4 to 11.9 m/s. Assuming the mean wind speed to vary stochastically in such range, the rotor design is optimized by minimizing mean and standard deviation of the levelized cost of energy (LCOE). Airfoil shapes, spanwise distributions of blade chord and twist, blade internal structural layup, and rotor speed are optimized concurrently, subject to structural and aeroelastic constraints. The probabilistically designed turbine achieves a more favorable probabilistic performance than the initial baseline turbine. The presented probabilistic design framework is portable and modular in that any of its analysis modules can be replaced with counterparts of user-selected fidelity.

scholarly journals Wind Turbine Design Optimization Under Environmental Uncertainty

2015 ◽  
Author(s):  
Marco Caboni ◽  
M. Sergio Campobasso ◽  
Edmondo Minisci
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Design Optimization ◽  
Rotor Design ◽  
Cost Of Energy ◽  
Mean Wind Speed ◽  
Significant Performance ◽  
The Mean ◽  
Wind Distribution ◽  
Turbine Design

Wind turbine design optimization is typically performed considering a given wind distribution. However, turbines so designed often end up being used at sites characterized by different wind distributions, and this results in significant performance penalties. This paper presents a probabilistic integrated multidisciplinary approach to the design optimization of multi-megawatt wind turbines accounting for the stochastic variability of the mean wind speed. The presented technology is applied to the design of a 5 MW rotor to be used at sites of wind power class from 3 to 7, where the mean wind speed at 50 m above the ground ranges from 6.4 to 11.9 m/s. Assuming the mean wind speed to vary stochastically in such range, the rotor design is optimized by minimizing mean and standard deviation of the levelized cost of energy. Airfoil shapes, spanwise distributions of blade chord and twist, internal structural layup and rotor speed are optimized concurrently, subject to structural and aeroelastic constraints. The probabilistically designed turbine achieves a more favorable probabilistic performance than the initial baseline turbine. The presented probabilistic design framework is portable and modular in that any of its analysis modules can be replaced with counterparts of user-selected fidelity.

scholarly journals Documenting Wind Speed and Power Deficits behind a Utility-Scale Wind Turbine

2013 ◽  
Vol 52 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Brian D. Hirth ◽  
John L. Schroeder
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Farm ◽  
Horizontal Wind ◽  
Horizontal Wind Speed ◽  
Large Variability ◽  
Cost Of Energy ◽  
The Mean ◽  
Utility Scale ◽  
Turbine Wake

AbstractHigh-spatial-and-temporal-resolution radial velocity measurements surrounding a single utility-scale wind turbine were collected using the Texas Tech University Ka-band mobile research radars. The measurements were synthesized to construct the first known dual-Doppler analyses of the mean structure and variability of a single turbine wake. The observations revealed a wake length that subjectively exceeded 20 rotor diameters, which far exceeds the typically employed turbine spacing of 7–10 rotor diameters. The mean horizontal wind speed deficits found within the turbine wake region relative to the free streamflow were related to potential reductions in the available power for a downwind turbine. Mean wind speed reductions of 17.4% (14.8%) were found at 7 (10) rotor diameters downwind, corresponding to a potential power output reduction of 43.6% (38.2%). The wind speed deficits found within the wake also exhibit large variability over short time intervals; this variability would have an appreciable impact on the inflow of a downstream turbine. The full understanding and application of these newly collected data have the potential to alter current wind-farm design and layout practices and to affect the cost of energy.

scholarly journals Aero-elastic Wind Turbine Design with Active Flaps for AEP Maximization

2017 ◽  
Author(s):  
Michael K. McWilliam ◽  
Thanasis K. Barlas ◽  
Helge A. Madsen ◽  
Frederik Zahle
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Integrated Design ◽  
Blade Design ◽  
Average Wind Speed ◽  
Peak Loads ◽  
Average Wind ◽  
Mean Wind Speed ◽  
Passive Strategies ◽  
Turbine Design

Abstract. In optimal wind turbine design, there is a compromise between maximizing the energy producing forces and minimizing the absolute peak loads carried by the structures. Active flaps are an attractive strategy because they give engineers greater freedom to vary the aerodynamic forces under any condition. Flaps can be used in a variety of different ways (i.e. reducing fatigue, peak loads etc.), however this article focuses on how quasi-static actuation as a function of mean wind speed can be used for Annual Energy Production (AEP) maximization. Numerical design optimization of the DTU 10 MW Reference Wind Turbine (RWT), with the HAWTOpt2 framework, was used to both find the optimal flap control strategy and the optimal turbine designs. The research shows that active flaps can provide a 1 % gain in AEP for aero-structurally optimized blades in both add-on (i.e. the flap is added after the blade is designed) and integrated (i.e. the blade design and flap angle is optimized together) solutions. The results show that flaps are complementary to passive load alleviation because they provide high-order alleviation, where passive strategies only provide linear alleviation with respect to average wind speed. However, the changing loading from the flaps further complicates the design of torsionally active blades, thus, integrated design methods are needed to design these systems.

scholarly journals Aero-elastic wind turbine design with active flaps for AEP maximization

2018 ◽  
Vol 3 (1) ◽  
pp. 231-241 ◽  
Author(s):  
Michael K. McWilliam ◽  
Thanasis K. Barlas ◽  
Helge A. Madsen ◽  
Frederik Zahle
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Integrated Design ◽  
Blade Design ◽  
Average Wind Speed ◽  
Peak Loads ◽  
Average Wind ◽  
Mean Wind Speed ◽  
Passive Strategies ◽  
Turbine Design

Abstract. In optimal wind turbine design, there is a compromise between maximizing the energy producing forces and minimizing the absolute peak loads carried by the structures. Active flaps are an attractive strategy because they give engineers greater freedom to vary the aerodynamic forces under any condition. Flaps can be used in a variety of different ways (i.e. reducing fatigue, peak loads), but this article focuses on how quasi-static actuation as a function of mean wind speed can be used for annual energy production (AEP) maximization. Numerical design optimization of the DTU 10 MW reference wind turbine (RWT), with the HAWTOpt2 framework, was used to both find the optimal flap control strategy and the optimal turbine designs. The research shows that active flaps can provide a 1 % gain in AEP for aero-structurally optimized blades in both add-on (i.e. the flap is added after the blade is designed) and integrated (i.e. the blade design and flap angle is optimized together) solutions. The results show that flaps are complementary to passive load alleviation because they provide high-order alleviation, where passive strategies only provide linear alleviation with respect to average wind speed. However, the changing loading from the flaps further complicates the design of torsionally active blades; thus, integrated design methods are needed to design these systems.

Interannual Wind Speed Variations and Estimated Wind Turbine Generator Energy Output at Selected Sites in the Pacific Northwest

1985 ◽  
Vol 107 (3) ◽  
pp. 237-239
Author(s):  
R. W. Baker
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Pacific Northwest ◽  
Power Measurement ◽  
Energy Output ◽  
Turbine Generator ◽  
Wind Turbine Generator ◽  
Speed Variation ◽  
Percent Increase ◽  
The Mean

The hourly wind speed data collected over a six-year period at four wind power measurement locations are used to estimate the annual energy output of a large wind turbine generator. The interannual energy and wind speed variations are discussed. The estimated interannual energy output at each location is related to the mean annual wind speed variation. The data indicate that at three of the four locations the estimated interannual energy variation varied as the square of the mean annual wind speed variation. That is, a 10 percent increase in the mean annual wind speed resulted in a 20 percent increase in the annual energy output. At the fourth location there was an approximate linear relationship.

Scale and Lag Effects on Control of Aerodynamic Power and Loads on a HAWT Rotor

2001 ◽  
Vol 123 (4) ◽  
pp. 339-345 ◽  
Author(s):  
P. J. Moriarty ◽  
A. J. Eggers, ◽  
K. Chaney ◽  
W. E. Holley
Keyword(s):  
Control System ◽  
Fatigue Life ◽  
Wind Speed ◽  
Open Loop ◽  
Time Lags ◽  
Large Power ◽  
Lag Effects ◽  
Mean Wind Speed ◽  
The Mean ◽  
High Control

The effects of rotor scale and control system lag were examined for a variable-speed wind turbine. The scale study was performed on a teetered rotor with radii ranging between 22.5m and 33.75m. A 50% increase in radius more than doubled the rated power and annual energy capture. Using blade pitch to actively control fluctuating flatwise moments allowed for significant reductions in blade mass for a fixed fatigue life. A blade operated in closed-loop mode with a 33.75m radius weighed less than an open-loop blade with a 22.5m radius while maintaining the same fatigue life of 5×109 rotations. Actuator lag reduced the effectiveness of the control system. However, 50% reductions in blade mass were possible even when implementing a relatively slow actuator with a 1 sec. time constant. Other practical limits on blade mass may include fatigue from start/stop cycles, non-uniform turbulence, tower wake effects, and wind shear. The more aggressive control systems were found to have high control accelerations near 60 deg/s2, which may be excessive for realistic actuators. Two time lags were introduced into the control system when mean wind speed was estimated in a rapidly changing wind environment. The first lag was the length of time needed to determine mean wind speed, and therefore the mean control settings. The second was the frequency at which these mean control settings were changed. Preliminary results indicate that quickly changing the mean settings (every 10 seconds) and using a moderate length mean averaging time (60 seconds) resulted in the longest fatigue life. It was discovered that large power fluctuations occurred during open-loop operation which could cause sizeable damage to a realistic turbine generator. These fluctuations are reduced by one half or more when aerodynamic loads are actively controlled.

scholarly journals Evaluation of the Power Output Performance Improvement of a 2 MW Wind Turbine

2018 ◽  
Vol 201 ◽  
pp. 01005
Author(s):  
Jui-Hung Liu ◽  
Jien-Chen Chen ◽  
Wen-Jhen Lai ◽  
Wei-Niam Su
Keyword(s):  
Wind Turbine ◽  
Performance Improvement ◽  
Control Strategy ◽  
Surface Condition ◽  
Operating Parameters ◽  
Base Line ◽  
Output Performance ◽  
Cost Of Energy ◽  
Mean Wind Speed ◽  
Large Wind

This paper shows the possibility of the output improvement to a large wind turbine, so the operator can earn more and thus reduce the overall cost of energy. For a modern wind turbine certificated by IEC or DNV-GL guidelines, a 20 years design lifetime is a base line. However, the efficiency of the turbine will degrade after 8 or 9 years’ operating. Some components, especially the turning blade, the efficiency may vary due to the surface condition change. Meanwhile, the controller technology may also have been improved after years. So, the turbine can regain its original output or even have a better output performance through some adjustments. In this paper, a 2 MW wind turbine with different design and operating parameters like blade efficiency, wind direction alignment, high/low wind control strategy has been evaluated, then with the software DNV-GL BLADED simulation, to calculate the output differences and availability of the turbine. The result shown that a 3~5% yield annually can be obtained for each improved parameter in a 9 m/s mean wind speed situation.

scholarly journals Local Climate Zone Classification Scheme Can Also Indicate Local-Scale Urban Ventilation Performance: An Evidence-Based Study

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 776 ◽  
Author(s):  
Ziqi Zhao ◽  
Lidu Shen ◽  
Liguang Li ◽  
Hongbo Wang ◽  
Bao-Jie He
Keyword(s):  
Wind Speed ◽  
Classification Scheme ◽  
Local Scale ◽  
Evidence Based ◽  
Weather Station ◽  
Local Climate ◽  
Mean Wind Speed ◽  
The Mean ◽  
Ventilation Performance ◽  
Local Climate Zone

Studies on urban ventilation indicate that urban ventilation performance is highly dependent on urban morphology. Some studies have linked local-scale urban ventilation performance with the local climate zone (LCZ) that is proposed for surface temperature studies. However, there is a lack of evidence-based studies showing LCZ ventilation performance and affirming the reliability of using the LCZ classification scheme to demonstrate local-scale urban ventilation performance. Therefore, this study aims to analyse LCZ ventilation performances in order to understand the suitability of using the LCZ classification scheme to indicate local-scale urban ventilation performance. This study was conducted in Shenyang, China, with wind information at 16 weather stations in 2018. The results indicate that the Shenyang weather station had an annual mean wind speed of 2.07 m/s, while the mean wind speed of the overall 16 stations was much lower, only 1.44 m/s in value. The mean wind speed at Shenyang weather station and the 16 stations varied with seasons, day and night and precipitation conditions. The spring diurnal mean wind was strong with the speeds of 3.56 m/s and 2.21 m/s at Shenyang weather station and the 16 stations, respectively. The wind speed (2.21 m/s at Shenyang weather station) under precipitation conditions was higher than that (1.75 m/s at Shenyang weather station) under no precipitation conditions. Downtown ventilation performance was weaker than the approaching wind background, where the relative mean wind speed in the downtown area was only 0.53, much less than 1.0. The downtown ventilation performance also varied with seasons, day and night and precipitation conditions, where spring diurnal downtown ventilation performance was the weakest and the winter nocturnal downtown ventilation performance was the strongest. Moreover, the annual mean wind speed of the 16 zones decreased from the sparse, open low-rise zones to the compact midrise zones, indicating the suitability of using LCZ classification scheme to indicate local-scale urban ventilation performance. The high spatial correlation coefficients under different seasons, day and night and precipitation conditions, ranging between 0.68 and 0.99, further affirmed that LCZ classification scheme is also suitable to indicate local-scale urban ventilation performance, despite without the consideration of street structure like precinct ventilation zone scheme.

Experimental investigation of aerodynamic vibrations of solar wing system

2018 ◽  
Vol 21 (15) ◽  
pp. 2217-2226 ◽  
Author(s):  
YC Kim ◽  
Y Tamura ◽  
A Yoshida ◽  
T Ito ◽  
W Shan ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Solar Panels ◽  
Boundary Layer Flows ◽  
Turbulence Flow ◽  
Aeroelastic Model ◽  
Mean Wind Speed ◽  
The Mean

The general characteristics of aerodynamic vibrations of a solar wing system were investigated through wind tunnel tests using an aeroelastic model under four oncoming flows. In total, 12 solar panels were suspended by cables and orientated horizontally. Distances between panels were set constant. Tests showed that the fluctuating displacement increases proportionally to the square of the mean wind speed for all wind directions in boundary-layer flows. Larger fluctuating displacements were found for boundary-layer flows with larger power-law indices. Under low-turbulence flow, the fluctuating displacement increased proportionally to the square of the mean wind speed for wind directions between 0° and 30°, but an instability vibration was observed at high mean wind speed for wind directions larger than 40°. And when the wind direction was larger than 60°, a limited vibration was observed at low mean wind speed and the instability vibration was also observed at high mean wind speed. Fluctuating displacements under grid-generated flow showed a similar trend to that of the boundary-layer flows, although the values became much smaller.

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