K–ω SST (shear stress transport) turbulence model calibration: A case study on a small scale horizontal axis wind turbine

Abstract

This work deals with a computational investigation emphasized on the calibration of a turbulence model regarding to the operational capability of a SS-HAWT (small-scale horizontal axis wind turbine). Experimental field tests were carried out to collect data to evaluate the performance (power) coefficient, Cp, as a function of the tip-speed ratio, λ. The prototype examined was a three-bladed wind turbine (NACA (National Advisory Committee for Aeronautics) 0012 profile) designed for fixed tip-speed ratio (with λ = 5), constructed and operated at the Federal University of Ceará. The maximum value experimentally achieved for Cp was about 14%. The k–ω SST (shear stress transport) turbulence model, solved by the open source CFD (computational fluid dynamics) toolbox OpenFOAM (Open Source Field Operation and Manipulation), assessed the wind turbine performance. The experimental data information obtained reporting the aerodynamic performance of the SS-HAWT prototype was required to calibrate the model. The turbulence intensity and the characteristic length were studied in terms of the β∗ parameter. The power coefficient numerically predicted tends to agree with the experimental assessment. The variation of β∗ mainly affects viscous friction over the blades.