著者

溝口 誠 麻生 茂

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.55, no.637, pp.74-81, 2007 (Released:2007-04-10)

参考文献数

12

被引用文献数

3 2

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A numerical analysis of a piston motion in a free piston driver has been conducted including a diaphragm rupture. Quasi-one-dimensional flow is assumed in the driver. Various losses, which are generated in a compression process, are simplified. A process of the diaphragm rupture is assumed by Outa’s model. Experiments are also conducted by using a free piston shock tunnel. Calculated pressure histories show excellent agreements with experimental results. The numerical analysis shows that the piston motion is strongly affected by the diaphragm rupture. Especially, pressure histories in front of the piston change significantly with compact compression tubes. Diaphragm opening time is necessary to be considered to increase test time and to obtain soft landing conditions in compact free piston drivers.

著者

赤塚 純一 西島 寛典 渡辺 光則 永井 伸治

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.60, no.5, pp.197-202, 2012 (Released:2012-10-23)

参考文献数

8

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This paper proposes a new method to predict an unstart of a supersonic wind tunnel. The pressure loss caused by both of a model and structures in the wind tunnel and cross-sectional area distribution are considered as well as blockage ratio in the conventional method. The prediction based on the proposed method was obtained by using quasi-1D numerical simulation. In order to validate the proposed method, a wind tunnel test was performed. The predicted maximum blockage ratios quite agreed with experimental ones except for a few cases in which strong shock wave-boundary layer interaction was observed. The method is expected to be available for various wind tunnels and it gives us more accurate prediction than that by conventional theory.

著者

大屋 裕二 烏谷 隆 桜井 晃

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.50, no.587, pp.477-482, 2002 (Released:2003-09-02)

参考文献数

11

被引用文献数

10 13

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We have developed a new wind turbine system that consists of a diffuser with a broad-ring brim at the exit periphery and a conventional wind turbine inside it. The new wind turbine has demonstrated power augmentation for a given turbine diameter and wind speed by a factor of about 2–3 compared with a bare wind turbine. This is because a very low-pressure region due to strong vortex formation behind the broad brim draws more mass flow to a turbine inside the diffuser.

著者

鈴木 真之 内山 賢治 Derek J. BENNET Colin R. MCINNES

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.59, no.693, pp.259-265, 2011 (Released:2011-10-21)

参考文献数

16

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This paper attempts to design a guidance law using bifurcating potential fields and velocity field for a swarm of autonomous Unmanned Aerial Vehicles (UAVs). We consider an autonomous flight system that can create different three-dimensional swarming patterns so as to guarantee obstacle and vehicle collision avoidance. The guidance law, which is derived from a steering and repulsive potential field, can express variable geometric patterns for a formation flight of UAVs. The system can transition between different formation patterns by way of a simple parameter change. We also describe the design method for potential field that is flexible enough to respond to a variety of UAV performance and mission. Numerical simulation is performed to verify the validity of the proposed guidance law.

著者

武田 和也 河島 信樹

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.51, no.594, pp.393-396, 2003 (Released:2003-09-26)

参考文献数

7

被引用文献数

2 3

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A full-size model of a lunar rover using a laser energy transportation to confirm directly the existence of ice on the moon has been fabricated and 100 m energy transportation test has been successfully performed. Problems to be solved to realize an actual lunar ice exploration mission are discussed.