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No.20 (1975/09) >

 
Title :Observation on the Vortex Rings
Authors :Igei, Ryokan
Issue Date :1-Sep-1975
Abstract :Observation was made on the vortex rings produced by ejecting dyed water into transparent water from a circular orifice of a glass tube of 0.75 cm in diameter. The translational velocity of the ring at the eight-diameter distance (6.0 cm) was used for the calculation of the Reynolds number. First, the graphs of the translational velocity vs. distance traveled by the ring plotted on semi -log paper indicate that in the later stage of the motion there exists an exponential type of dependence of the velocity on the distance, v" - exp ( - k y), the value of k depending on the Reynolds number, with k decreasing as the Reynolds number increases. Next, from the relation between the velocity and time elapsed plotted on log-log paper, it is found that when the power law approximation, v - t ^<-b>, is adopted for the later part of the motion, the value of bapproximately equals to 1 for each ring regardless the Reynolds number. Finally, our result suggeststs a linear relationship between the maximum distance traveled by the ring before its breakdown and the Reynolds number.
Type Local :紀要論文
Publisher :琉球大学理工学部
URI :http://hdl.handle.net/20.500.12000/23529
Citation :琉球大学理工学部紀要. 理学編 = Bulletin of Science & Engineering Division, University of Ryukyus. Mathematics & natural sciences no.20 p.15 -22
Appears in Collections:No.20 (1975/09)

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