Large eddy simulations of wind turbine wakes in typical complex topographies

Abstract

There is a need to clarify the coupling characteristics of terrain-induced wind fields and wind turbine-induced wake in wind farm micrositing. However, research investigating the effect of hill shape on this interaction is lacking. In addition, during the optimization of the layout of the turbines over topographies, the flow behind the turbines should be predicted in a fast way. After obtaining the wake flow of the turbine mounted on flat terrain and the flow over the topographies, there are mainly two superposition methods to predict the turbine wake flow over the topographies.One is to add the wind deficit following the location with a vertical distance of the hub height (D-line). The other is to add the wind deficit following the streamline starting from the turbine center (B-line). It remains unknown to what extent these two superposition methods can be adopted. Therefore, the effects of hill shape, wind turbine size, and turbine location are investigated. When the wind deficit, obtained from modeling the wake flow of the turbine mounted on flat terrain, is superposed following B-line, the results are overall better than those when following D-line.

Large eddy simulation of an onshore wind farm under different operating regimes including topographic effects

“…LES-ALM simulations are performed in [18] of a wind farm of 60 wind turbines in complex terrain, assessing the mean power production and power fluctuations. Several authors have analyzed canonical cases through LES showing a complex interaction between wakes and the wind flow casued by hills (see for instance [19,20]).…”

The characteristics of weather-related wind load parameters and wind 2 power quality over the Dabanchen strong gale area

“…Considering the importance of the turbulence integral scale (abbreviated TIS) and the power spectral density (abbreviated PSD) of fluctuating winds under the condition of abnormal strong winds and their effects on gust factor estimation and turbulence kinetic energy, which are important considerations for various structural wind-resistance designs (Davenport, 1961;Davenport and Sparling, 1992;Zhou et al, 2017;Kozmar et al,2021;Liu et al,2020;ASCE/SEI 7-16, 2017;AIJ, 2019), we examine special cases to characterize the distributions of these parameters compared to international standard codes and typhoon-affected areas in this work.…”

“…appear to be modified by the terrain α or 𝑧 # , although the α and 𝑧 # values are not essential factors in producing turbulence, which can also be related to atmospheric stability, such as nonstationary wind (i.e., squall lines or downbursts). The theorical foundations of both codes including numerical simulation experiments for wind turbine fatigue load calculation (He et al, 2020;Liu et al,2020;Ren et al,2018), which are based on stationary winds for relatively open flat areas and on wind tunnel tests, are not directly applied for large, complex mountainous terrain frequently accompanied by unstable stratification synoptics. It is very difficult for these methods to accurately reflect rapid and high-amplitude nonstationary wind evolution processes due to either ignoring the large-scale synoptic background or restrictions imposed by wind tunnel sizes and configurations.…”

The characteristics of weather-related wind load parameters and wind power quality over the Dabanchen strong gale area

“…Therefore, the extent of turbulence seems to be an inherent property of α or 𝑧𝑧 0 , and the designed TI profiles (𝐼𝐼 𝑧𝑧 ) appear to be modified by the terrain α or 𝑧𝑧 0 , although the α and 𝑧𝑧 0 values are not essential factors in producing turbulence, which can also be related to atmospheric stability, such as nonstationary wind (i.e., squall lines or downbursts). The theorical foundations of both codes including numerical simulation experiments for wind turbine fatigue load calculation (He et al, 2020;Liu et al,2020;Ren et al,2018), which are based on stationary winds for relatively open flat areas and on wind tunnel tests, are not directly applied for large, complex mountainous terrain frequently accompanied by unstable stratification synoptics. It is very difficult for these methods to accurately reflect rapid and high-amplitude nonstationary wind evolution processes due to either ignoring the large-scale synoptic background or restrictions imposed by wind tunnel sizes and configurations.…”

“…Considering the importance of the turbulence integral scale (abbreviated TIS) and the power spectral density (abbreviated PSD) of fluctuating winds under the condition of abnormal strong winds and their effects on gust factor estimation and turbulence kinetic energy, which are important considerations for various structural wind-resistance designs (Davenport, 1961;Davenport and Sparling, 1992;Zhou et al, 2017;Kozmar et al,2021;Liu et al,2020;ASCE/SEI 7-16, 2017;AIJ, 2019), we examine special cases to characterize the distributions of these parameters compared to international standard codes and typhoon-affected areas in this work. Then, we qualitatively analyze the reliability and application conditions of these parameters.…”