HISAKI Project Team

大友 衆示

オオトモ シュウジ  (Shūji Ōtomo)

基本情報

所属
東京農工大学 大学院工学府 助教
国立研究開発法人宇宙航空研究開発機構(JAXA) 宇宙科学研究所(ISAS) (大学共同利用システム研究員)
学位
PhD(2021年11月 The University of Edinburgh)

ORCID ID
 https://orcid.org/0000-0002-0344-3961
J-GLOBAL ID
202101007887437023
researchmap会員ID
R000015471

外部リンク

学歴

 3

主要な論文

 12
  • Shūji Ōtomo, Stefano Gambuzza, Yabin Liu, Anna M. Young, Riccardo Broglia, Edward D. McCarthy, Ignazio Maria Viola
    Physics of Fluids 36(067122) 2024年6月1日  査読有り筆頭著者
  • James M. Maguire, Dimitrios Mamalis, Shūji Ōtomo, Edward D. McCarthy
    Composite Structures 337 118090-118090 2024年6月  査読有り
  • Shūji Ōtomo, Yuji Tasaka, Petr Denissenko, Yuichi Murai
    Physics of Fluids 36 2024年2月1日  査読有り筆頭著者責任著者
    With an increasing demand for small energy generation in urban areas, small-scale Savonius wind turbines are growing their share rapidly. In such an environment, Savonius turbines are exposed to low mean velocity with highly turbulent flows made by complex geographies. Here, we report the flow-induced rotation of a Savonius turbine in a highly turbulent flow (18% turbulence intensity). The high turbulence is realized by using the far-field of an open-jet. Compared to low turbulence inflow (1% turbulence intensity), the turbine rotates 4% faster in high turbulence since the torque/power increases with turbulence intensity. The wake measurement by hot-wire anemometry and particle image velocimetry reveals the suppression of vortex shedding in high turbulence. In addition, a newly developed semi-empirical low-order model, which can include the effect of turbulence intensity and integral length scale, also confirms high turbulence intensity contributes to the rotation of the turbine. These results will boost more installation of small Savonius turbines in urban areas in the future.
  • Shūji Ōtomo, Sabrina Henne, Karen Mulleners, Kiran Ramesh, Ignazio Maria Viola
    Experiments in Fluids 62(1) 2021年1月  査読有り筆頭著者
    The ability to accurately predict the forces on an aerofoil in real-time when large flow variations occur is important for a wide range of applications such as, for example, for improving the manoeuvrability and control of small aerial and underwater vehicles. Closed-form analytical formulations are only available for small flow fluctuations, which limits their applicability to gentle manoeuvres. Here we investigate large-amplitude, asymmetric pitching motions of a NACA 0018 aerofoil at a Reynolds number of 3.2 × 10 4 using time-resolved force and velocity field measurements. We adapt the linear theory of Theodorsen and unsteady thin-aerofoil theory to accurately predict the lift on the aerofoil even when the flow is massively separated and the kinematics is non-sinusoidal. The accuracy of the models is remarkably good, including when large leading-edge vortices are present, but decreases when the leading and trailing edge vortices have a strong interaction. In such scenarios, however, discrepancies between the theoretically predicted and the measured lift are shown to be due to vortex lift that is calculated using the impulse theory. Based on these results, we propose a new limiting criterion for Theodorsen’s theory for a pitching aerofoil: when a coherent trailing-edge vortex is formed and it advects at a significantly slower streamwise velocity than the freestream velocity. This result is important because it extends significantly the conditions where the forces can be confidently predicted with Theodorsen’s formulation, and paves the way to the development of low-order models for high-amplitude manoeuvres characterised by massive separation. Graphic abstract: [Figure not available: see fulltext.].

MISC

 3
  • 髙田 直輝, 渡辺 綾乃, 下村 怜, 大友 衆示, 西田 浩之
    2023年11月  
  • 村井 祐一, 大友 衆示, 田坂 裕司, デニセンコ ペトロ
    動力・エネルギー技術の最前線講演論文集 : シンポジウム 2019 C211 2019年  
    Influence of high-intensity turbulence to the performance of a Savonious wind turbine has been investigated experimentally. The turbulent intensity and its isotropic quality are managed in a large wake region of an open-jet type wind tunnel. We have found that the rotational speed of the turbine rather increases with hep of turbulence as a constant load was subject to the turbine. This robustness to the inflow quality is attributed to the drag acting on the blade being intensified by the turbulence. Hot-wire anemometer measurement of the flow behind the turbine revealed that periodic vortex-shedding due to the blade-passing frequency was suppressed with strong turbulence in the inflow.
  • Shuji OTOMO, Susumu OSUKA, Yuji TASAKA, Yuichi MURAI, Petr DENISSENKO
    The Proceedings of Conference of Hokkaido Branch 2016.54 79-80 2016年  筆頭著者

講演・口頭発表等

 4

担当経験のある科目(授業)

 2

所属学協会

 1

主要な共同研究・競争的資金等の研究課題

 4