Shūji Ōtomo

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Verified

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• PhD
• Professor (Assistant) at Tokyo University of Agriculture and Technology

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...

An accurate non-intrusive force measurement is challenging in many situations, especially those involving animals and vehicles. This paper reports a non-intrusive technique based on the vortex force map (VFM) method, which computes forces from snapshot velocity and vorticity fields obtained from the particle image velocimetry (PIV) flow measurement...

Mitigating the impact of variable inflow conditions is critical for a wide range of engineering systems such as drones or wind and tidal turbines. Passive control systems are of increasing interest for their inherent reliability, but a mathematical framework to aid the design of such systems is currently lacking. To this end, in this paper a two-di...

Numerical simulations and lab-scale experiments are used to evaluate three passively morphing trailing edge designs for a composite tidal turbine blade. The designs include a closed trailing edge, an open trailing edge, and a corrugated trailing edge. It is shown that geometric stiffness, as well as material stiffness, play key roles in achieving t...

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 turb...

Savonius wind turbines have attracted attention to generate electric power in urban areas subject to high turbulence. To further improve the performance, we designed a spherical Savonius turbine expecting robustness to the change in wind direction and speed. The inflow angle was varied between 0 and 180 degrees. In addition, the performance was com...

An accurate non-intrusive force measurement is challenging in many situations especially those involving animals and vehicles. This paper reports a non-intrusive technique based on the vortex force map (VFM) method, which computes forces from snapshot velocity and vorticity fields obtained from the particle image velocimetry (PIV) flow measurement....

Air flow field around narrowly arrayed out-door units of air conditioners is investigated experimentally under real-world operation conditions. The air flow velocities at the intake panels and exhaust ports of individual units are measured using hot-wire anemometry. The velocity data are analyzed upon Eulerian grid space to reconstruct the three-di...

Tidal currents are renewable and predictable energy sources that could prove fundamental to the transition to a sustainable use of renewable energy resources. Over a tidal period, changes in the flow speed in a tidal channel require that the blade pitch is adjusted to maximise power extraction. This is currently achieved with active pitch actuation...

Unsteady lifting-line theory (ULLT) is a low-order method capable of modeling interacting unsteady and finite wing effects at low computational cost. Most formulations of the method assume inviscid flow and small amplitudes. Although these assumptions might be suitable for small-amplitude aeroelastic problems at high Reynolds numbers, modern engine...

Unsteady Lifting-Line Theory (ULLT) is a low order method capable of modeling interacting unsteady and finite wing effects at low computational cost. Most formulations of the method assume inviscid flow and small amplitudes. Whilst these assumptions might be suitable for small-amplitude aeroelastic problems at high Reynolds numbers, modern engineer...

The unsteady vortex lattice method is modified with a leading edge wake shedding criterion and a regularized vortex particle wake for application to problems involving leading edge vortices on finite wings. The leading edge vortex structures obtained using this low order method are compared against CFD data for a pitching maneuver. To model seven c...

Savonius wind turbines are utilized in urban area subject to high turbulence. Past studies for the turbine were conducted for the turbulence intensity lower than 10%. We conducted a series of wind tunnel experiments at high turbulent intensity over 15%, using the space downstream of a large free jet where isotropic turbulence occurs obeying Kolmogo...

Respiratory droplets are the primary transmission route for SARS-CoV-2, a principle which drives social distancing guidelines. Evidence suggests that virus transmission can be reduced by face coverings, but robust evidence for how mask usage might affect safe distancing parameters is lacking. Accordingly, we set out to quantify the effects of face...

Respiratory droplets are the primary transmission route for SARS-CoV-2. Evidence suggests that virus transmission can be reduced by face coverings, but robust evidence for how mask usage might affect safe distancing parameters is lacking. Accordingly, we investigate the effectiveness of surgical masks and single-layer cotton masks on mitigating dis...

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...