EFFECTS OF TERRAIN AND ATMOSPHERIC THERMAL STABILITY ON WIND VELOCITY PROFILES
The wind of the atmospheric boundary layer serves as the incoming flow and kinetic energy source for wind turbines. It remains one of the most challenging flows in fluid dynamics research due to a wide range of spatial and temporal turbulent scales that need to be resolved simultaneously. Also, it is not well established how wind velocity responds to complex terrain of a site and variations in atmospheric thermal stability.
This research aims to characterize vertical wind profiles in the surface layer according to different terrain features and the atmospheric thermal stability (as determined by the gradient Richardson Number). Data sets were recorded by multiple different instruments mounted at various levels of a 106-meter tall meteorological tower at the Kirkwood Community College in Cedar Rapids, Iowa. Vertical profiles of mean wind speed and temperature for an entire year have been analyzed based on terrain features and the thermal stability. These
profiles are compared to the 1/7th power law, which is commonly used to estimate the wind speed at turbine hub heights by extrapolating wind data at lower elevations. This work provides insights into the effects of terrain and the atmospheric thermal stability on wind profiles, crucial for assessing the onshore wind resource during planning and predicting wind loads on turbines in operation.