Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 03, 2023 - September 06, 2023
In order to investigate the influence of the oscillating amplitude ratio to the lock-in range of the circular cylinder which is carrying out the forced oscillation in the direction of a flow, the closed circuit water channel apparatus was used and flow visualization observation was carried out. The used visualization method is a pouring streak method. The experiment was performed combining four kinds of circular cylinder diameters (8, 12, 16, and 32 mm), and four kinds of oscillating half amplitude (2, 4, 6, and 8 mm). All of the flow velocity of those experiments was carried out by 0.04 m/s. Even if changes of the flow pattern at the time of a lock-in differed in the circular cylinder diameter, they were the same. However, when circular cylinder diameters differed also with the same circular cylinder oscillation frequency, it was found that the configurations of the lock-in differ. In the combination of the circular cylinder diameter and oscillating half amplitude, when the oscillating amplitude ratio was the same, it was confirmed that the range of the lock-in becomes almost the same. The lock-in range when the oscillating amplitude ratio is larger than 1 was shown. When the oscillating amplitude ratio increased, it was found that the lock-in range tends to narrow.
