Instituto de Física, Universidade Federal do Rio de Janeiro, C.P. 68528, CEP: 21945-970, Rio de Janeiro, RJ, Brazil.
Phys Rev E. 2019 Oct;100(4-1):043102. doi: 10.1103/PhysRevE.100.043102.
The interpretation of data obtained from particle image and tracking velocimetry in the study of superfluid flows has been so far a challenging task. Tracking particles (as solid hydrogen or deuterium) are attracted to the cores of quantized vortices, so that their dynamics can be strongly affected by the surrounding vortex tangle. Previous phenomenological arguments indicate that tracking particles and microsized vortex rings could form bound states (denoted here as VRP states). While a comprehensive description of the vortex ring-particle bonding mechanism has to deal with somewhat involved flow configurations, we introduce a simplified two-dimensional model of VRP states, which captures essential qualitative features of their three-dimensional counterparts. Besides an account of known experimental and numerical observations, the model proves to be of great heuristic interest. In particular, it sheds light on the important role played by viscous dissipation (due to the normal component of the fluid), the Magnus force, and topologically excited vortex rings in the stability and dynamics of VRP states.
迄今为止，从粒子图像和示踪测速法获得的数据解释一直是一项具有挑战性的任务。追踪粒子（如固态氢或氘）会被量子涡旋的核心吸引，因此它们的动力学可能会受到周围涡旋缠结的强烈影响。先前的唯象论点表明，追踪粒子和微尺度涡旋环可以形成束缚态（这里表示为 VRP 态）。虽然要全面描述涡旋环-粒子键合机制需要处理稍微复杂的流动配置，但我们引入了一个简化的二维 VRP 态模型，它捕获了其三维对应物的基本定性特征。除了对已知的实验和数值观察的解释外，该模型还具有很大的启发意义。特别是，它揭示了粘性耗散（由于流体的法向分量）、马格努斯力以及拓扑激发的涡旋环在 VRP 态的稳定性和动力学中的重要作用。
