%0 Electronic Article %A Y. Kinoshita %+ Dept. of Mech. Eng., Doshisha Univ., Kyoto %A Y. Yamasaki %+ Dept. of Mech. Eng., Doshisha Univ., Kyoto %A H. Mihara %+ Gen. Building Res. Corp. of Japan, Osaka %A T. Inoue %+ Dept. of Mech. Eng., Doshisha Univ., Kyoto %A J. Funaki %+ Dept. of Mech. Eng., Doshisha Univ., Kyoto %A K. Hirata %+ Dept. of Mech. Eng., Doshisha Univ., Kyoto %K torque measurement %K thickness-to-breadth ratio %K aerodynamic characteristics %K subsonic wind-tunnel experiments %K mixers %K T-mode-II torque mode %K autorotating finite flat plate %K waterwheels %K flat plate tumbling %K neutral tip-speed ratio %K T-mode-I torque mode %K plate attack angle %K flow visualisations %K aspect ratio %K torque coefficient %K power coefficient %K synchronised measurements %K torquemeter %K diffusers %K vertical-axis windmill %K phase-averaging technique %K uniform mainstream %K hot-wire anemometer %X We conduct subsonic wind-tunnel experiments, in order to investigate the basic aerodynamic characteristics of an autorotating finite flat plate in uniform mainstream, which has a potential for new windmills and water-wheels with very simple structures in addition to new mixers/diffusers. The present study focuses on both the effects of an aspect ratio AR and a tip-speed ratio Q* upon the tumbling of the flat plate with a low thickness-to-breadth ratio λ = 2.0 × 10-2 - 5.0 × 10-2. We carry out the measurements using a torquemeter together with the synchronised measurements of the plate's attack angle α for the analyses with phase-averaging technique, in addition to measurements using a hot-wire anemometer and flow visualisations. As a result, the torque coefficient CT linearly decreases with increasing 0*, and CT tends to become large with increasing AR. Then, neutral tip-speed ratio ΩP*CT0 where CT crosses zero tends to become large with increasing AR. Power coefficient CP shows similar tendencies with CT. In addition, we confirm that there exist two torque modes T-mode I and T-mode II, and the transition between them. The T-mode I tends to appear at low AR and low Ω*. And, the T-mode II tends to appear at high AR and high Q*. %T Torque measurement on a simple vertical-axis windmill using a finite flat plate %B IET Conference Proceedings %D January 2014 %P 102 (6 .)-102 (6 .) %I Institution of Engineering and Technology %U https://digital-library.theiet.org/;jsessionid=17i0gyirkqgwd.x-iet-live-01content/conferences/10.1049/cp.2014.1224 %G EN