Dipartimento di Fisica e Astronomia "Galileo Galilei" and CNISM, Università di Padova, via Marzolo 8, 35122 Padova, Italy.
Departament FQA, Facultat de Física, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain.
J Chem Phys. 2023 Apr 14;158(14):144306. doi: 10.1063/5.0143399.
The instability of a cryogenic He jet exiting through a small nozzle into vacuum leads to the formation of He drops, which are considered ideal matrices for spectroscopic studies of embedded atoms and molecules. Here, we present a He-density functional theory (DFT) description of droplet formation resulting from jet breaking and contraction of superfluid He filaments. Whereas the fragmentation of long jets closely follows the predictions of linear theory for inviscid fluids, leading to droplet trains interspersed with smaller satellite droplets, the contraction of filaments with an aspect ratio larger than a threshold value leads to the nucleation of vortex rings, which hinder their breakup into droplets.
低温氦射流通过小喷嘴进入真空时的不稳定性会导致氦液滴的形成，氦液滴被认为是嵌入原子和分子光谱研究的理想基质。在这里，我们提出了一种基于密度泛函理论（DFT）的模型，用于描述由于射流断裂和超流氦细丝收缩而导致液滴形成的过程。虽然长射流的碎裂过程与无粘流体的线性理论预测非常吻合，导致液滴串之间夹杂着较小的卫星液滴，但当细丝的纵横比大于某个阈值时，细丝的收缩会导致涡旋环的成核，从而阻碍其碎裂成液滴。
