Evaluating the accuracy of the actuator line model against blade element momentum theory in uniform inflow

Wind Energy

Bruno S. Carmo¹  Luoqin Liu²  Daniel F. Oliveira³  Flavio C.C. Galeazzo⁴  Richard J. A. M. Stevens⁵  Lucas Franceschini⁵ 

[1] Department of Mechanical Engineering, Escola Politécnica University of São Paulo São Paulo Brazil;Department of Modern Mechanics University of Science and Technology of China Hefei Anhui China;Department of Naval Architecture & Ocean Engineering, Escola Politécnica University of São Paulo São Paulo Brazil;High Performance Computing Center Stuttgart (HLRS), University of Stuttgart Stuttgart Germany;Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics University of Twente Enschede The Netherlands;

关键词: actuator line model;    blade element momentum;    large eddy simulation;   

DOI  :  10.1002/we.2714

来源: DOAJ

【 摘 要 】

Abstract We evaluate the accuracy of the actuator line model (ALM) approach by performing simulations for the NREL 5‐MW wind turbine in uniform inflow using three large eddy simulation codes. The power and thrust coefficients obtained using the three codes agree within 1% when the grid spacing Δgrid≤5.25 m and are cross‐validated against blade element momentum (BEM) theory. We find that the results of ALM converge towards BEM theory without the need for tip correction when the numerical resolution is increased. For Δgrid=0.98 m, the difference between the power and thrust coefficient obtained using ALM and BEM is 4.5% and 2.1%, respectively, although we note that no absolute convergence between ALM and BEM can be obtained as both models use different assumptions, such as the use of a force projection method in the ALM. The difference in the local axial and tangential forces along the blades obtained from ALM simulations using Δgrid=1.97 m and Δgrid=0.98 m can be as large as 10%. The effect of the number of actuator points on the obtained turbine power and thrust coefficients is limited as the results converge when the spacing between the actuator points is about three times the grid spacing. This insight on the required number of blade points can be used to improve the efficiency of actuator line simulations.

【 授权许可】

Unknown