Free-surface dynamics of small pores

Dynamical transitions during the collapse of inertial holes

“…Figure 3a illustrates the evolution of the rate of contraction v m with minimum hole radius r m for a low-viscosity hole of Oh = 0.018. As expected for this small Ohnesorge number, the hole velocity follows the scalingwhere α ≈ 0.57, indicating that the contraction initiated by surface tension is now dominated by inertia 20,34,38 . Indeed, for the contraction of an axisymmetric cavity in a fluid of negligible viscosity, Eggers et al .…”

“…Results show that the simulations (black line) agree well with the experiments (symbols). Moreover, in the early stages of contraction, the experiments confirm the existence of an inertial regime (top red line) in which the data approximately follow the rate of collapse expected for an inviscid liquid 20,34,38 . Similarly, in the vicinity of pinch off, when the minimum hole radius r m → 0, the dynamics enters a final viscous regime (bottom red line) in which the data follow the theoretical rate of collapse corresponding to a Stokes liquid 21,24,35 .…”

“…Mesh independence studies were carried out at various resolutions, and meshes with degrees of freedom between approximately 15000 and 20000 degree of freedom were selected depending on the Oh . We have previously benchmarked and successfully applied this numerical scheme to simulate similar free-surface flows, including drop coalescence 32 , breakup of Newtonian and non-Newtonian liquid filaments 33 , collapse of viscous and inertial pores 34,35 , and contraction of surfactant-laden pores and filaments 36,37 .…”

Universal Scaling Law for the Collapse of Viscous Nanopores

“…Results also show that the scaling law is nearly independent of the macroscopic length scales of the nanopores. Contrary to the terminal Taylor−Culick speed of large expanding pores 4,15,16 and the increasing speed of collapse of small inertial pores, 10 which both depend on the sheet thickness, the terminal speed for viscous collapsing nanopores depends only on the fluid properties.…”

Soft food microrheology

“…by capillarity). Recently, rigorous theories elucidating the interplay between endogenous capillary forces and the hydrodynamics of embedded microscopic pores and indentations have been developed (McGraw et al, 2011;Rahmani et al, 2014;*Backholm et al, 2014;Lu and Corvalan, 2015;*Lu et al, 2015), and applied to relate the motion of the probe "micropores" (Fig. 2a) to the Newtonian (Fig.…”