Effects of incoming surface wind conditions on the wake characteristics and dynamic wind loads acting on a wind turbine model

2014 ◽  
Vol 26 (12) ◽  
pp. 125108 ◽  
Author(s):  
Wei Tian ◽  
Ahmet Ozbay ◽  
Hui Hu
Author(s):  
Ahmet Ozbay ◽  
Wei Tian ◽  
Hui Hu

An experimental study was carried out to investigate the aeromechanics and wake characteristics of dual-rotor wind turbines (DRWTs) with co- and counter-rotating configurations, in comparison to those of a conventional singlerotor wind turbine (SRWT), in order to elucidate the underlying physics to explore/optimize design of wind turbines for higher power yield and better durability. The experiments were performed in a large-scale Aerodynamic/Atmospheric Boundary Layer (AABL) wind tunnel under neutral stability conditions. In addition to measuring the power output performance of DRWT and SRWT systems, static and dynamic wind loads acting on those systems were also investigated. Furthermore, a high resolution PIV system was used for detailed near wake flow field measurements (free-run and phase-locked) so as to quantify the near wake turbulent flow structures and observe the transient behavior of the unsteady vortex structures in the wake of DRWT and SRWT systems. In the light of the promising experimental results on DRWTs, this study can be extended further to investigate the turbulent flow in the far wake of DRWTs and utilize multiple DRWTs in different wind farm operations.


Author(s):  
Wei Tian ◽  
Ahmet Ozbay ◽  
Hui Hu

An experimental study was conducted to compare the characteristics of the dynamic wind loads and evolution of the unsteady vortex and turbulent flow structures in the wake of a wind turbine sited in onshore and offshore wind farms. A scaled three-blade Horizontal Axial Wind Turbine (HAWT) model was placed in Atmospheric Boundary Layer (ABL) winds with different mean and turbulence characteristics to simulate the wind conditions in onshore and offshore wind farms. In addition to measuring dynamic wind loads acting on the wind turbine model by using a high-sensitive force-moment sensor unit, a high-resolution digital Particle Image Velocimetry (PIV) system was used to achieve flow field measurements to quantify the characteristics of the turbulent flow in the wake of the wind turbine model. Besides conducting “free-run” PIV measurements to determine the ensemble-averaged statistics of the flow quantities such as mean velocity, Reynolds stress, and Turbulence Kinetic Energy (TKE) distributions in the wake, “phase-locked” PIV measurements were also performed to elucidate further details about evolution of the unsteady vortex structures in the wake flow in relation to the position of the rotating turbine blades. The detailed flow field measurements are correlated with the dynamic wind loads measurements to elucidate underlying physics in order to gain further insight into changes of the dynamic wind loads and wake characteristics behind the wind turbine operating in either onshore or offshore wind farms.


2021 ◽  
Author(s):  
Haoran Meng ◽  
Hao Su ◽  
Jia Guo ◽  
Timing Qu ◽  
Liping Lei

Abstract A wind-tunnel experimental study was performed to investigate the impact of the surge and sway motions of a wind turbine model on the power output, rotor thrust and wake characteristics. A wind turbine model was mounted on a translation platform to simulate the surge and sway motions under given amplitude and frequency. The power output and rotor thrust of the turbine model subjected to surge and sway motions were measured by using a DC variable electronic load and a six-component force sensor, respectively. For comparison, these measurements were also performed in a bottom-fixed wind turbine. The results show that the mean power output and mean rotor thrust of the turbine model under surge and sway motions are almost the same as those of the bottom-fixed turbine. However, the thrust fluctuation amplitude of the turbine model under surge motion is significantly higher than those of the turbine model under sway motion and the bottom-fixed turbine. In addition, the wake characteristics of the turbine model were also investigated by using a particle image velocimetry system. The results show that the surge and sway motions have slight effect on the near and intermediate wake of the turbine model in the horizontal plane at the rotor hub height.


Author(s):  
W. Schünemann ◽  
R. Schelenz ◽  
G. Jacobs ◽  
W. Vocaet

AbstractThe aim of a transfer path analysis (TPA) is to view the transmission of vibrations in a mechanical system from the point of excitation over interface points to a reference point. For that matter, the Frequency Response Functions (FRF) of a system or the Transmissibility Matrix is determined and examined in conjunction with the interface forces at the transfer path. This paper will cover the application of an operational TPA for a wind turbine model. In doing so the path contribution of relevant transfer paths are made visible and can be optimized individually.


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