HOME    About this site    mypage    Japanese    library    university    Feedback

University of the Ryukyus Repository >
Faculty of Engineering >
Bulletin >
The Bulletin of Science and Engineering Division University of the Ryukyus >
No.17 (1979/03) >

 
Title :魚の泳動に関する研究
Title alternative :Study on swimming of fish
Authors :永井, 實
真栄田, 義才
伊良部, 邦夫
Authors alternative :Nagai, Minoru
Maeda, Gisai
Irabu, Kunio
Issue Date :1-Mar-1979
Abstract :Though it is well known that some aquatic animals can swim at higher speed than the value estimated from both of the muscle power and the friction drag received from the stream around the animal, the reason of such a high speed propulsion seems not yet to be solved. In this study, first, the swimming abilities of the various swimmers involving small fishes, dolphins, whales and a manmade submarine for reference were rearranged in a logarithmic chart and the subject of the problem was settled quantitatively. Then, measurements of drag force of some fishes by a towing type instrument with strain guage and observations of the swimming motion of fishes by a high speed camera were carried out in the water channel of laboratory. According to the experimental results, there is no evidence of that the skin friction of fish is smaller than that of the solid boundary of axi-symmetrical body in the experimental range of Reynolds number between 5X10⁴ and 5X10⁵. And it was found that swimming speed of fishes is proportional to the body length and the oscillating frequency of the tail fin. Then, a new dimensionless number u/(f・ℓ) was introduced as a swimming number. In the present observations, the swimming numbers of fish of three species were coincident each other at the value of 0.6, and this value also agreed with other species of a previous investigation.
Type Local :紀要論文
ISSN :0387-429X
Publisher :琉球大学理工学部
URI :http://hdl.handle.net/20.500.12000/27574
Citation :琉球大学理工学部紀要. 工学篇 = Bulletin of Science & Engineering Division, University of the Ryukyus. Engineering no.17 p.15 -21
Appears in Collections:No.17 (1979/03)

Files in This Item:

File Description SizeFormat
No17P015.pdf2477KbAdobe PDFView/Open