A Simple Model for the Turbulence Intensity Distribution in Atmospheric Boundary Layers

Abstract

In the current work, we examine the distribution of turbulence intensity (TI) in simulations of atmospheric boundary layers (ABL) for wind turbine applications. We relate the turbulent fluctuations to the mean wind shear profile for neutrally stable ABL based on turbulent boundary layer theory. The results are then compared to corresponding LES data for various shear conditions. From this, a model for the TI distribution across a rotor disc is devised and calibrated. In addition, a second simpler version of the model is derived by assuming a power law for the velocity profile. The models are related to the Mann model and shown to have a similar scaling, however they are simpler and based on assumptions for turbulent boundary layers rather than homogeneous turbulence. The models are then tested for a range of stability conditions and shear values of the ABL including waked conditions from upstream wind turbines that stretch the assumptions made.