Study on the Turbulent Flow of Superfluid 4He Generated by a Vibrating Wire
Study on the Turbulent Flow of Superfluid 4He Generated by a Vibrating Wire
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DOI：
10.1063/1.2354663
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发表时间：
2006-12
影响因子：
0.8
通讯作者：
H. Yano;A. Handa;M. Nakagawa;K. Obara;O. Ishikawa;T. Hata
中科院分区：
文献类型：
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作者：
H. Yano;A. Handa;M. Nakagawa;K. Obara;O. Ishikawa;T. Hata
我们研究了振弦产生的超流体 4He 的流动。随着驱动力的增加，金属丝的速度在层流状态下增加，直到在湍流状态开始时突然下降。随着驱动力减小，湍流在临界速度处消失。这一结果表明，即使在湍流中，导线上的涡流也被限制在有限的尺寸内。我们测量了谐振频率范围为 0.5 kHz 至 9 kHz 的 7 根振弦在 1.4 K 下的临界速度，发现临界速度在低于 2 kHz 振荡频率时几乎恒定，而在该频率以上则增加。我们还观察了 30 mK 低温下超流体 4He 中振弦的响应。我们发现，在流动进入湍流状态的同一时刻，共振频率会向上跳跃。频率跳跃可能是由涡流动力学引起的，例如管道中发生的膨胀、纠缠和重新连接。
We have studied the flow of superfluid 4He generated by a vibrating wire. As the drive force increases, the velocity of the wire grows in the laminar‐flow regime, until it suddenly drops at the onset of the turbulent‐flow regime. As the drive force decreases, the turbulence disappears at a critical velocity. This result suggests that the vortices on the wire are confined within a finite size, even in turbulence. We have measured the critical velocity of seven vibrating wires, whose resonance frequencies range from 0.5 kHz to 9 kHz, at 1.4 K and found that the critical velocity is almost constant below an oscillation frequency of 2 kHz and increases above this frequency. We have also observed the response of a vibrating wire in superfluid 4He at a low temperature of 30 mK. We find that the resonance frequency jumps upward at the same moment as the entry of the flow to a turbulent state. The frequency jump may be caused by vortex dynamics such as expansion, entanglement, and reconnection occurring in the tu...