著者

伊藤 慎一郎 加瀬 光輝

出版者

一般社団法人 日本機械学会

雑誌

流体工学部門講演会講演論文集 2013 (ISSN:24242896)

巻号頁・発行日

pp._G1104-01_-_G1104-03_, 2013-11-09 (Released:2017-06-19)

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A flying disc can fly through the air because of the combination of the lift and drag forces by the oncoming air flow. Actual fight conditions were confirmed to perform the wind tunnel experiment beforehand. In order to clarify the mechanism of flight of flying discs, the flow field structure and the fluid force were investigated on non-spinning and spinning conditions. In the fluid force measurement, lift and drag forces were taken by varying wind speeds, spin speeds, and angle of attack. Drag and lift forces were found to increase as spin increased. The angle of attack on the maximum range of lift-drag ratio or glide ratio was found to be wide from 6 to 13 degrees which was suitable for a long distance throwing. Using a smoke wind tunnel, flow visualization around the disc was performed in order to understand the effect of disc spin. It was found that spin enhances lift force by attracting the Coanda effect on the trailing edge.

著者

吉田 直之 加瀬 篤志 田地川 勉 板東 潔

出版者

一般社団法人 日本機械学会

雑誌

流体工学部門講演会講演論文集 2013 (ISSN:24242896)

巻号頁・発行日

pp._1202-01_-_1202-03_, 2013-11-09 (Released:2017-06-19)

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The purpose of this study is elucidating the mechanism of mosquito's flight. The motion of mosquito's wings consists of three representative motion; flapping, lead-lug and feathering motion. The feathering motion is a rotational movement which is centering on a wing leading edge. The mosquitoes are performing this motion passively produced by fluid forces and so on. In order to build the enlarged model which simulates this motion, we need to measure the stiffness of the mosquito's wings. The bending stiffness of the mosquito's wings were measured by the experiment using a cantilever. The enlarged wing model was designed based on its results. We observed the flapping motion of the enlarged wing model in the very low velocity wind tunnel and verified whether the feathering motion can be simulated.

著者

細谷 直人 山川 勝史 松野 謙一

出版者

一般社団法人 日本機械学会

雑誌

流体工学部門講演会講演論文集 2013 (ISSN:24242896)

巻号頁・発行日

pp._G0401-01_-_G0401-02_, 2013-11-09 (Released:2017-06-19)

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The most difficult way to prevent infection among some infection routes is viral droplet nuclei transmission. Droplet nuclei are generated during coughing and sneezing, and suspend for a long time. Hence, specifying its infection route is important issue. The behavior of the droplets is governed by the physical principles. In addition, environmental factors, such as temperature, relative humidity and droplet size, also affect their dispersion and determining the survival. Thus, in this paper, first airflow in the crowded train was analyzed by using CFD.