论文标题
从MK温度下的超氟 ^4E中振荡的微球从微球中脱落的涡流和从Bose-Einstein冷凝物中移动的激光束
Vortex shedding from a microsphere oscillating in superfluid ^4He at mK temperatures and from a laser beam moving in a Bose-Einstein condensate
论文作者
论文摘要
振荡的微球的动荡阻力在MK温度下以超流体$^4 $ He悬浮，略高于关键速度振幅$ v_c $的不稳定。动荡状态的寿命$τ$取决于每半期涡流棚的数量$ n $。发现此数字与超氟雷诺数相同。考虑到在Microkelvin温度下通过超氟$^3 $移动悬浮球的可能性。通过Bose-Einstein冷凝物（BEC）移动的激光束（其他作者观察到）也会在BEC中产生涡流。特别是，在任何一种情况下，都可以观察到脱落频率$ f_v $在$ΔV= -V -v_c $上的线性依赖性，其中$ v $是球体的速度振幅或激光束的速度幅度或$ v_c $ the $ v_c $的速度的持续速度，用于驱动的频率：$ f_v = aΔv$ aΔv= aΔv$ aΔv=一些特征频率$ω_k$，并假定稳定运动的有限值$ω\ rightarrow 0 $。呈现与经典湍流不同的超氟雷诺数与超流体杂种数之间的关系。
Turbulent drag of an oscillating microsphere, that is levitating in superfluid $^4$He at mK temperatures, is unstable slightly above a critical velocity amplitude $v_c$. The lifetime $τ$ of the turbulent state is determined by the number $n$ of vortices shed per half-period. It is found that this number is identical to the superfluid Reynolds number. The possibility of moving a levitating sphere through superfluid $^3$He at microkelvin temperatures is considered. A laser beam moving through a Bose-Einstein condensate (BEC) (as observed by other authors) also produces vortices in the BEC. In particular, in either case a linear dependence of the shedding frequency $f_v$ on $Δv = v - v_c$ is observed, where $v$ is the velocity amplitude of the sphere or the constant velocity of the laser beam above $v_c$ for the onset of turbulent flow: $f_v = a Δv$, where the coefficient $a$ is proportional to the oscillation frequency $ ω$ above some characteristic frequency $ω_k$ and assumes a finite value for steady motion $ω\rightarrow 0$. A relation between the superfluid Reynolds number and the superfluid Strouhal number is presented that is different from classical turbulence.
