The experiment was carried out to compare the
performance of the VAWT, without and with the use of
the ODGV, and the results are shown in Fig. 8. The
experimental results show that the rotational speed of the
VAWT increases from 51 rpm to 115 rpm, 94 rpm and
109 rpm for the three configurations, i.e. 0 degree, 30
degrees and 60 degrees respectively. From Fig. 8, the
rotational speed of the VAWT increases more rapidly
compared to the bare VAWT, this trend shows that the
ODGV improves the response of the wind turbine to
on-coming wind. Comparing these results, the VAWT
gives the highest increment in rotational speed when the
wind was blown from the direction of 0 degree of the
ODGV. The most important finding is that the presence
of the ODGV successfully increases the rotational kinetic
energy of the wind rotor. The stabilized rotor rotational
speed and percentage increment for each configuration
are summarized in Table 4. Overall, the increment of
rotational speed is about 108%. The feasibility of the
ODGV to improve the performance of the wind rotor has
been proved via this simple experiment