On wind turbine loads during the evening transition period
Journal
Wind Energy
Journal Volume
22
Journal Issue
10
Pages
1288-1309
Date Issued
2019
Author(s)
Abstract
The late afternoon hours in the diurnal cycle precede the development of the nocturnal stable boundary layer. This “evening transition” (ET) period is often when energy demand peaks. This period also corresponds to the time of day that is a precursor to late-afternoon downbursts, a subject of separate interest. To capture physical characteristics of wind fields in the atmospheric boundary layer (ABL) during this ET period, particularly the interplay of shear and turbulence, stochastic simulation approaches, although more tractable, are not suitable. Large-eddy simulation (LES), on the other hand, may be used to generate high-resolution ABL turbulent flow fields. We present a suite of idealized LES four-dimensional flow fields that define a database representing different combinations of large-scale atmospheric conditions (characterized by associated geostrophic winds) and surface boundary conditions (characterized by surface heat fluxes). Our objective is to evaluate the performance of wind turbines during the ET period. Accordingly, we conduct a statistical analysis of turbine-scale wind field variables. We then employ the database of these LES-based inflow wind fields in aeroelastic simulations of a 5-MW wind turbine. We discuss how turbine loads change as the ET period evolves. We also discuss maximum and fatigue loads on the rotor and tower resulting from different ABL conditions. Results of this study suggest that, during the ET period, the prevailing geostrophic wind speed affects the mean and variance of longitudinal winds greatly and thus has significant influence on all loads except the yaw moment which is less sensitive to uniform and symmetric incoming flow. On the other hand, surface heat flux levels affect vertical turbulence and wind shear more and, as a result, only affect maximum blade flapwise bending and tower fore-aft bending loads. ? 2019 John Wiley & Sons, Ltd.
Subjects
Atmospheric boundary layer
Atmospheric thermodynamics
Atmospheric turbulence
Flow fields
Heat flux
Large eddy simulation
Stochastic models
Stochastic systems
Turbulence
Turbulent flow
Wind
Wind turbines
Aero-elastic simulations
Atmospheric conditions
evening transition
inflow
Physical characteristics
Stochastic simulations
Surface boundary conditions
Wind turbine loads
Meteorology
boundary condition
boundary layer
geostrophic flow
heat flux
large eddy simulation
turbulence
wind field
wind shear
wind turbine
wind velocity
SDGs
Type
journal article