ABSTRACT The wind turbine with a flanged-diffuser shroud—so called “wind-lens turbine”—is developed as one of high performance wind turbines by Ohya et al. In this paper, the wind turbine performance is investigated for both steady and unsteady winds. The compact-type wind lens turbine shows higher efficiency than the only rotor wind turbine. Also, the flow structure around the compact-type wind turbine is made clear by CFD and PIV in steady wind. Furthermore, the performances of the only rotor and the compact-type wind-lens turbines for unsteady wind are experimentally and numerically investigated. Experimental and numerical results are presented to demonstrate the dependence of frequency of the harmonic oscillating velocity wind on power coefficient. Consequently, the compact-type wind-lens turbine show better performance than the only rotor one in sinusoidally oscillating velocity wind. Furthermore, the numerical estimation can predict the power coefficient in the oscillating flows to an accuracy of 94% to 102%. In addition, the dependence of the turbine performance on turbulent intensity and vortex scale of natural fluctuating wind is presented.
Cite this paper
K. Toshimitsu, H. Kikugawa, K. Sato and T. Sato, "Experimental Investigation of Performance of the Wind Turbine with the Flanged-Diffuser Shroud in Sinusoidally Oscillating and Fluctuating Velocity Flows," Open Journal of Fluid Dynamics, Vol. 2 No. 4, 2012, pp. 215-221. doi: 10.4236/ojfd.2012.24A024.
 Y. Ohya and T. Karasudani, “A Shrouded Wind Turbine Generating High Output Power with Wind-Lens Technology,” Journal of Energies, Vol. 3, No. 4, 2010, pp. 643649.
 K. Toshimitsu, K. Nishikawa, W. Haruki, S. Oono, M. Takao and Y. Ohya, “PIV Measurement of Flows around the Wind Turbines with a Flanged-Diffuser Shroud,” Journal of Thermal Science, Vol. 17, No. 4, 2008, pp. 375380.
 T. Karasudani, Y. Ohya and K. Watanabe, “On the Response of Small Wind Turbine to Changes of Wind Speed and Load,” Journal of Japan Wind Energy Association, Vol. 31, No. 2, 2007, pp.120-123. (in Japanese)
 T. Karasudani, Y. Ohya and K. Watanabe, “On the Power of a Wind Turbine with Fixed-Pitch Angle Wings for Sinusoidally Changing Wind Speed,” Journal of Japan Wind Energy Association, Vol. 32, No. 1, 2008, pp. 128132. (in Japanese)
 M. Okino, S. Iba, T. Karasudani, Y. Ohya and K. Watanabe, “Effect of Atmospheric Turbulence on Wind Turbine Performance,” Proceedings of the 29th Symposium of Wind Energy Utilization, Tokyo, 2007, pp. 310-313. (in Japanese)
 Y. Sugita, M. Ueda and M. Furukawa, “Flow Structure around a Wind Turbine Shrouded by Compact-Type Brimmed Diffuser,” Proceedings of JSME Fluid Engineering Conference 2005 (CD-ROM ISSN 1348-2882), Kanazawa, 2005, Paper No. 1819. (in Japanese)