著者

湯沢 峰司 大上 芳文

出版者

一般社団法人日本機械学会

雑誌

年次大会講演論文集 : JSME annual meeting

巻号頁・発行日

vol.2002, no.3, pp.333-334, 2002-09-20

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A tailless aircraft is known as an airplane with the merit of little air drag since the tail and the fuselage, which connects the main wing with the tail plane, do not exist. It also has the demerit of instability in maneuvering in the longitudinal direction. Our team at Ritsumeikan University has been daring to participate in the birdman-rally with the tailless aircraft, but a good result has not yet been obtained. The purpose of this paper is to study and to develop the tailless aircraft for the birdman-rally by computational fluid dynamics. The data of the flight at the last rally were analyzed, and the problems and solutions were obtained.

著者

福留 功二 刺刀 一匡 大上 芳文

出版者

一般社団法人 日本機械学会

雑誌

関西支部講演会講演論文集 2014.89 (ISSN:24242756)

巻号頁・発行日

pp._9-3_, 2014-03-18 (Released:2017-06-19)

著者

大上 芳文 赤松 映明

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. B編 (ISSN:03875016)

巻号頁・発行日

vol.55, no.510, pp.298-305, 1989-02-25

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A numerical investigation is carried out to examine the validity of the unsteady Kutta condition presented by many authors. Using a vortex method with a diffusion velocity model, the flow under a transient and oscillating motion of a NACA 0012 airfoil at Re=10000 is calculated. It is found that after the airfoil starts impulsively from rest, the rear stagnation point moves to the trailing edge instantly. Then the angle between the stream line from the trailing edge and the edge bisector decreases from 90° to 10° for the nondimensional time 0 to 0.1. After that time, the classical Kutta condition gradually becomes satisfied. In an oscillating motion, the rear stagnation point is always on the trailing edge and the amplitude of the angle of stream line direction from the trailing edge increases with the frequency. This result shows that the classical Kutta condition is always violated in an oscillating motion.

著者

小國 稔記 大上 芳文

出版者

一般社団法人日本機械学会

雑誌

関西支部講演会講演論文集

巻号頁・発行日

vol.2000, no.75, pp."3-23"-"3-24", 2000-03-16

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A winglet is one of the wing-tip plates to prevent the formation of wing-tip vortices which cause a decrease of Cl (Lift Coefficient) / Cd (Drag Coefficient). The ground effect causes an increase of Cl/Cd of airfoils in proximity to the ground. Therefore, the winglets and the ground effect have the same function. Birdman's glider or WIG (wing in ground) use both of them. Aerodynamics characteristics of the winglets in the ground effect are, however, not well-known. The purpose of this paper is to study the optimum design of winglets in the ground effect by computational fluid dynamics. In concluding, the best angle is a dihedral angle of 45 degrees for winglets in ground effect.