Abstract
The flow and noise characteristics of wake behind wind-turbine blades have been investigated experimentally using a two-frame particle image velocimetry (PIV) technique. Experiments were carried out in a POSTECH subsonic large wind-tunnel (<TEX>$1.8^W{\times}1.5^H{\times}4.3^L\;m^3$</TEX>) with KBP-750D (3-blade type) wind-turbine model at a freestream velocity of <TEX>$U_o\;=\;15\;m/s$</TEX> and a tip speed ratio <TEX>$\lambda\;=\;6.14$</TEX> (2933 rpm). The wind-turbine blades are connected to an AC servo motor, brake, encoder and torque meter to control the rotational speed and to extract a synchronization signal for PIV measurements. The wake flow was measured at four azimuth angles (<TEX>$\phi\;=\;0^{\circ}$</TEX>, <TEX>$30^{\circ}$</TEX>, <TEX>$60^{\circ}$</TEX> and <TEX>$90^{\circ}$</TEX>) of the wind-turbine blade. The dominant flow structure of the wake is large-scale tip vortices. The turbulent statistics such as turbulent intensity are weakened as the flow goes downstream due to turbulent dissipation. The dominant peak frequency of the noise signal is identical to the rotation frequency of blades. The noise seems to be mainly induced by the tip vortices.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
