The controlled dynamical generation of radial dam break flows (DBFs) is demonstrated in two-dimensional droplet environments. These ultracold mixtures feature competing mean-field and quantum fluctuation effects and are initialized on a disk-shaped uniform density. Depending on the value of the latter, reflecting also the dominance of attractive or repulsive interactions, three dynamical response regimes are identified. At small densities a moving wavetrain of bright ring solitons is observed (dubbed ring DBF), at intermediate densities a ring kink-dispersive shock wave, while at large densities the flows encompass composite ring kink-rarefaction waves moving towards the center. The emergence of these patterns, whose formation would be prohibited in two-dimensional Kerr media due to wave-collapse, is rooted in the competition between attraction and repulsion inherent to droplet environments, modeled by the extended Gross-Pitaevskii equation. The characterization of the ensuing nonlinear waveforms is further corroborated by reduced models based on the cubic-quintic nonlinear Schr\"odinger equation. The different wave patterns emanating from dam break flows can be experimentally realized using current state-of-the-art ultracold atom experiments.
Abstract Content of image described in text. This study combines linear stability analysis (LSA) and direct numerical simulations (DNS) to investigate the coupling mechanisms of rotation, stratification and shear in two flow geometries: spanwise rotating stratified plane Couette flow (between two infinite parallel plat...
Zhou-Xin Jiang, Sheng-Qi Zhang, J. Hao et al.· Journal of Fluid Mechanics· 0 citations
When an obstacle moves through a compressible medium, it creates a density perturbation. Theoretical arguments regarding the shape of this density wake in Brownian suspensions either suppose infinite dilution or describe only the far field. Here, we study via experiments and numerical simulations the closing of the den...
G. Duprez, Gianmarco Spera, Benjamin Buhl et al.· 0 citations
Invasion of solid tumours is often mediated by heterogeneous cell populations that differ in motility, adhesion, and proliferation. Motivated by these mechanisms, we study a two-population continuum model in which the total density generates a pressure field and cell transport follows a Darcy-type law, coupled to growt...
P. Ciarletta, M. Magri, D. Shkurti et al.· Journal of Mathematical Biol...· 0 citations
In this study, a two-dimensional lattice Boltzmann method is employed to numerically investigate the collective dynamics of squirmer–passive particle mixtures in a channel filled with power-law fluids. Particular attention is paid to the effects of the power-law index n, propulsion type β, and squirmer fraction c on th...
Abstract Content of image described in text. We explored the collective sedimentation of non-convex ring-shaped particles in viscous suspensions using direct numerical simulations based on the smoothed profile method. The toroidal particle geometry introduces an internal flow pathway that allows fluid penetration, fund...
Bilal Fareed, Muhammad Nadeem, Soohyeon Kang et al.· Journal of Fluid Mechanics· 0 citations
Abstract Content of image described in text. The deformation and breakup of drops in turbulent flows play a key role in a variety of industrial processes and natural situations. Literature reviews link the breakup of a droplet into two droplets (known as binary breakup) to a critical deformed state (CDS). Based on the...
Ignacio Roa, F. Thiesset, M. Renoult et al.· Journal of Fluid Mechanics· 1 citation
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