Yu Nishio

<p>This paper proposes a measurement system to detect locally high temperature spaces. The indoor spaces of a building with unique design tend to have uneven temperature distribution. Therefore, energy consumption required for air conditioning control increases. It is thought that the energy efficiency required for air conditioning control would be improved if locally high temperature space can be measured and the information feedback to the controller. In this study, a measurement system using a mobile robot was developed to measure the temperature distribution of indoor spaces. We experimented using this system in a library with a unique design and succeeded to detect locally high temperature spaces.</p>

<p>A tube-type gas burner consists of a straight tube with a slit along it and discharges an air-gas mixture through the slit to produce a flame. The flow velocity from the slit depends on the pressure in the tube and the pressure loss at the slit, and it varies in the longitudinal direction of the tube. The resulting uneven flame degrades the quality of the burner. In this study, we develop a one-dimensional theoretical model of the flow in a tube with a slit. To validate the result of the theoretical model, we also conduct experiments and numerical simulations for the same flow field. We applied this theoretical model to a flow in a tube, 1m length, 40mm in diameter, with a slit 2.5mm wide. The end of the tube is closed. We also discuss the effect of the length of the burner on the unevenness.</p>

This study develops a gust wind tunnel, which allows us to investigate aerodynamic characteristics of a body under an unsteady flow. First, a simple wind tunnel model with one fan is developed, and its performance is investigated. It is found that the stall of fans is the cause of the insufficient acceleration of the gust. The employment of exhaust ports improves the acceleration. Four simple wind tunnel models are combined to make a multi-fan gust wind tunnel, and its performance is investigated. As a result, it is found that the acceleration of the gust increases by approximately 20 % of the previous wind tunnel. In addition, the freestream disturbance of the proposed gust wind tunnel is drastically reduced.

<p>Numerical simulations of a thin liquid film flow scattering from a flat disk and a bell cup which are rotating are performed using an incompressible SPH (Smoothed Particle Hydrodynamics) method. The influence of grooves near the edges on the formations of ligaments and droplets is investigated by changing the number and the shapes of the grooves under different flow conditions. It is found that small droplets of uniform size are likely to be generated when the grooves are present, especially for the bell cup atomizer.</p>

<p>Behavior of a sphere exposed to a sudden water flow in a U-channel is simulated using an incompressible SPH (Smoothed Particle Hydrodynamics) method. New computational models are proposed which improve the handling of the rotational motion of the sphere and the buoyancy acting on the sphere. An experiment is also performed to validate the computational models. It is shown that the simulation can accurately predict the translational movement of the sphere. However, the computed rotational angle of the sphere is smaller than the experimental result.</p>

<p>A new airfoil for straight-bladed vertical axis wind turbines is designed by a genetic algorithm and two-dimensional vortex method aimed at improving both the starting performance and efficiency at a cruising condition, which is the tip-speed ratio of λ = 2.0. The new airfoil has a negative camber and its aerodynamic performance is remarkably improved at the second and the third quadrants in the rotating plane, compared with the conventional NACA0018 airfoil.</p>

<p>Boundary layer receptivity to a sheet-type disturbance is experimentally investigated using an airfoil-shaped disturbance generator, which is installed upstream of an elliptical leading edge of a flat plate. The velocity fluctuation taken into the boundary layer first decays and then grows algebraically downstream. Stationary streaky structures, in which high- and low-speed regions are aligned in the spanwise direction, are found inside the boundary layer. The observation of the velocity waveform suggests that parts of hairpin vortices exist frequently observed between the high- and low-speed regions in the streaky structures.</p>

<p>Splashing behavior of a thin liquid film on a rotating disk is simulated by an incompressible SPH method to evaluate the effect of the grooves at the disk edge of a liquid atomizer. When the number of grooves is larger than the averaged number of ligaments in the clean disk condition, the same number of ligaments as the grooves are generated at the disk edge. Under the condition, the generated droplets tend to have similar sizes.</p>