Abstract:The impact of solid and liquid objects (projectiles) onto liquids and soft solids (targets) generally results on the creation and expansion of an air cavity inside the impacted objects. The...
“…However, depending on the Weber number the cavity can collapse below the original position of the surface (deep seal; figure 2 a ) or from the top of surface (surface seal; figure 2 b ). The shapes of the cavities and bubbles entrapped are similar to those of impacts on capillary bridges (Quetzeri-Santiago & Rivas 2023). In these experiments we observe deep seal for , while surface seal is observed for (see figure 2).…”
Section: Resultssupporting
confidence: 53%
“…We attribute these discrepancies to the uniform velocity across the jet in the simulations, which is not the case for the experiments. Furthermore, we note that the characteristics of cavity collapse and Worthington jet formation are influenced by small disturbances of the cavity and the shape of the jet plays a major role (Michon, Josserand & Séon 2017; Quetzeri-Santiago & Rivas 2023). Figure 3.( a ) Superposition of cavity profiles by cylindrical jets at , for different Weber numbers, indicating inverse relation between rim thickness and Weber number.…”
Section: Resultsmentioning
confidence: 94%
“…The set-up is similar to those used in Quetzeri-Santiago et al. (2021) and Quetzeri-Santiago & Rivas (2023). The thermocavitation process occurs inside a glass microfluidic chip filled with a Direct Red 81 solution in water at 0.5 wt%.…”
Section: Methodsmentioning
confidence: 99%
“…2018; Quetzeri-Santiago et al. 2021; Quetzeri-Santiago & Rivas 2023). For cavities generated by projectiles in the millimetre range, collapse can be mainly attributed to the hydrostatic pressure (Oguz et al.…”
Studying liquid jet impacts on a liquid pool is crucial for various engineering and environmental applications. During jet impact, the free surface of the pool deforms and a cavity is generated. Simultaneously, the free surface of the cavity extends radially outward and forms a rim. Eventually the cavity collapses by means of gas inertia and surface tension. Our numerical investigation using an axisymmetric model in Basilisk C explores cavity collapse dynamics under different impact velocities and gas densities. We validate our model against theory and experiments across a previously unexplored parameter range. Our results show two distinct regimes in the cavity collapse mechanism. By considering forces pulling along the interface, we derive scaling arguments for the time of closure and maximum radius of the cavity, based on the Weber number. For jets with uniform constant velocity from tip to tail and
$We \leqslant 150$
, the cavity closure is capillary-dominated and happens below the surface (deep seal). In contrast, for
$We \geqslant 180$
the cavity closure happens above the surface (surface seal) and is dominated by the gas entrainment and the pressure gradient that it causes. Additionally, we monitor gas velocity and pressure throughout the impact process. This analysis reveals three critical moments of maximum gas velocity: before impact, at the instant of cavity collapse and during droplet ejection following cavity collapse. Our results provide information for understanding pollutant transport during droplet impacts on large bodies of water, and other engineering applications, like additive manufacturing, lithography and needle-free injections.
“…However, depending on the Weber number the cavity can collapse below the original position of the surface (deep seal; figure 2 a ) or from the top of surface (surface seal; figure 2 b ). The shapes of the cavities and bubbles entrapped are similar to those of impacts on capillary bridges (Quetzeri-Santiago & Rivas 2023). In these experiments we observe deep seal for , while surface seal is observed for (see figure 2).…”
Section: Resultssupporting
confidence: 53%
“…We attribute these discrepancies to the uniform velocity across the jet in the simulations, which is not the case for the experiments. Furthermore, we note that the characteristics of cavity collapse and Worthington jet formation are influenced by small disturbances of the cavity and the shape of the jet plays a major role (Michon, Josserand & Séon 2017; Quetzeri-Santiago & Rivas 2023). Figure 3.( a ) Superposition of cavity profiles by cylindrical jets at , for different Weber numbers, indicating inverse relation between rim thickness and Weber number.…”
Section: Resultsmentioning
confidence: 94%
“…The set-up is similar to those used in Quetzeri-Santiago et al. (2021) and Quetzeri-Santiago & Rivas (2023). The thermocavitation process occurs inside a glass microfluidic chip filled with a Direct Red 81 solution in water at 0.5 wt%.…”
Section: Methodsmentioning
confidence: 99%
“…2018; Quetzeri-Santiago et al. 2021; Quetzeri-Santiago & Rivas 2023). For cavities generated by projectiles in the millimetre range, collapse can be mainly attributed to the hydrostatic pressure (Oguz et al.…”
Studying liquid jet impacts on a liquid pool is crucial for various engineering and environmental applications. During jet impact, the free surface of the pool deforms and a cavity is generated. Simultaneously, the free surface of the cavity extends radially outward and forms a rim. Eventually the cavity collapses by means of gas inertia and surface tension. Our numerical investigation using an axisymmetric model in Basilisk C explores cavity collapse dynamics under different impact velocities and gas densities. We validate our model against theory and experiments across a previously unexplored parameter range. Our results show two distinct regimes in the cavity collapse mechanism. By considering forces pulling along the interface, we derive scaling arguments for the time of closure and maximum radius of the cavity, based on the Weber number. For jets with uniform constant velocity from tip to tail and
$We \leqslant 150$
, the cavity closure is capillary-dominated and happens below the surface (deep seal). In contrast, for
$We \geqslant 180$
the cavity closure happens above the surface (surface seal) and is dominated by the gas entrainment and the pressure gradient that it causes. Additionally, we monitor gas velocity and pressure throughout the impact process. This analysis reveals three critical moments of maximum gas velocity: before impact, at the instant of cavity collapse and during droplet ejection following cavity collapse. Our results provide information for understanding pollutant transport during droplet impacts on large bodies of water, and other engineering applications, like additive manufacturing, lithography and needle-free injections.
We investigate the interfacial dynamics involved in the impact of a droplet on a liquid− liquid system, which involves the impingement of an immiscible core liquid drop from a vertical separation onto an interfacial shell liquid layer floating on a host liquid bath. The dynamics have been studied for a wide range of impact Weber numbers and two different interfacial shell liquids of varying volumes. The core drop, upon impact, dragged the interfacial liquid into the host liquid, forming an interfacial liquid column with an air cavity inside the host liquid bath. The dynamics is resolved into cavity expansion and rapid contraction, followed by thinning of the interfacial liquid. The interplay of viscous dissipation, interfacial pull, and core drop inertia influenced the necking dynamics. The viscous dissipation increases with the thickness of the interfacial layer, which depends on the volume and lateral spread over the water. The necking dynamics transitioned from inertia-dominated deep seal closure at higher spread, lower interfacial film volumes, and higher Weber numbers into inertia-capillary-dominated deep seal closure with an increase in film volumes, decrease in the spread of the interfacial fluid, or decrease in Weber number and finally into a no-seal closure at high volumes, low spread, and low Weber numbers.
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