COMPARATIVE STUDY OF CFD AND THE DMST APPLIED TO DARRIEUS H-ROTOR PERFORMANCE CALCULATIONS

Resumo

CFD and other vortex methods are used to predict the performance of horizontal and vertical
axis wind turbines and investigate the wake effects with good precision. The main drawback of these
methods that they usually consume a lot of computational time and consequently expensive for quick
evaluation studies. There are other numerical methods that can be useful for this type of application
needing less computational time and reasonably accurate. One of such numerical methods is the blade
element momentum (BEM) for horizontal axis wind turbine and double multiple stream tube (DMST)
for vertical axis wind turbine. This work reports the results of a comparative study between CFD,
experimental measurements and the DMST to predict the performance of Darrieus H-rotor type vertical
axis wind turbines (VAWTs). The DMST combines the multiple stream tube model with the double
actuator disk theory. The results from the present study compared the CFD results with the present
Matlab DMST code incorporating Xfoil. The DMST overestimated the power coefficient but presented
similar behavior when compared with other numerical and experimental results. The overestimated
values are mainly due to the fact that the wake is not accounted for in a simultaneous way as is the case
in the experiments and CFD simulations.