Characteristics of the transition to turbulence in superfluid He4 at low temperatures
Characteristics of the transition to turbulence in superfluid He4 at low temperatures
复制标题
低温超流He4的湍流转变特征
DOI：
10.1063/1.3009577
复制
发表时间：
2008
影响因子：
0.8
通讯作者：
M. Blazhkova
中科院分区：
文献类型：
--
作者：
G. Sheshin;A. Zadorozhko;E. Rudavskii;V. Chagovets;L. Skrbek;M. Blazhkova
用浸没在液体中的压电石英振荡器（音叉）对He Ⅱ的动力学和耗散过程进行了实验研究。在0.1K ~ 4.2K温度范围内，用不同的激励电压测量了音叉在共振频率附近的电响应。共振曲线的半宽度的测量值使得有可能确定在宽的温度范围内的正常组分的He II的粘度。有效粘度的最大值被发现在温度为10.5K，这是由于一个最大的过渡从流体动力学的弹道制度中的声子气体在He II。它是建立在音叉的振荡的低速度的速度是一个线性函数的激振力;这对应于层流的液体在边界层附近的振荡表面。主要的耗散过程与正常组分的粘度有关。计算结果表明，边界层的厚度随温度的升高而增大。
A piezoquartz oscillator (tuning fork) immersed in liquid is used to study the kinetic and dissipative processes in He II experimentally. The electrical response of the tuning fork near its resonance frequency is measured with different exciting voltages at temperatures ranging from 0.1Kto4.2K. The measured values of the half-width of the resonance curves made it possible to determine the viscosity of the normal component of He II in a wide temperature range. A maximum of the effective viscosity is found at temperature ∼0.5K; this maximum is due to a transition from the hydrodynamic to the ballistic regime in the phonon gas in He II. It is established that for low velocities of oscillation of the tuning fork the velocities are a linear function of the excitation force; this corresponds to laminar flow of the liquid in the boundary layer near the oscillating surface. The main dissipative process is associated with the viscosity of the normal component. The thickness of the boundary layer near the surface o...