On the Rotor Effects upon Nacelle Anemometry for Wind Turbines

Abstract

The objective of this paper is to study the typical atmospheric turbulent flow around the rotor and nacelle of a HAWT, in order to (i) investigate the impact of the turbine's rotating blades on the flow field over the nacelle, i.e. the rotor-nacelle interaction; (ii) assess the appropriate anemometer location on the nacelle, and therefore (iii) establish the relationship between wind speed measured near the nacelle and free stream wind speed. The paper presents a numerical method for investigating the effects of rotating rotor blades on the nacelle anemometry of a horizontal axis wind turbine (HAWT). The flow field around the turbine and nacelle is described by the Reynolds averaged Navier-Stokes equations. The k – ε model has been chosen for the closure of time-averaged turbulent flow equations. The rotor is modelled using the actuator-disk concept. The simulation results were performed using a commercial wind turbine rated at 750kW. In general, good qualitative agreements have been found, supporting the validity of the proposed method. However, quantitatively, the accuracy of the simulation results should be confirmed before any use is made in power performance testing.