Influence of time interval on the water entry of two spheres in tandem configuration

Lyu, Xujian; Yun, Honglu; Wei, Zhaoyu

doi:10.1007/s00348-021-03300-w

Cited by 14 publications

(1 citation statement)

References 39 publications

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“…In 2021, Lyu et al 84 conducted experimental investigations to examine the impact of the time interval between two tandem spheres entering the water on cavity evolution and the motion characteristics of the spheres. Their findings revealed that the time interval between the spheres influences the pattern of cavity closure for the rear sphere.…”

Section: Introductionmentioning

confidence: 99%

Parallel water entry: Experimental investigations of hydrophobic/hydrophilic spheres

Akbarzadeh,

Krieger,

Hofer

et al. 2023

Physics of Fluids

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This study aims to experimentally investigate the vertical parallel water entry of two identical spheres (in geometry and material) with different surface wettability (hydrophilic or hydrophobic) pairings. The spheres simultaneously impact the water surface with velocities ranging from 1.71 to 4.32 m s−1. The corresponding ranges of the impact Froude, Weber, and Reynolds numbers are 3.87–9.75, 816–5167, and 38.5×103 to 96.8×103, respectively. The spheres' lateral distances vary from 1.0 to 5.0 times the diameter. A high-speed photography system and image processing technique analyze the event dynamics, focusing on air-entrainment cavity behavior (shapes, closure, shedding), water flow features (Worthington jets, splashes), and sphere kinetics. Results for hydrophobic/hydrophobic cases show that even at the maximum lateral distance, a slightly asymmetric cavity forms, but deep-seal pinching occurs at a single point, similar to a single water entry scenario. As the lateral distance decreases, the spheres significantly influence each other's behavior, leading to the formation of a highly asymmetric air cavity and an oblique Worthington jet. In the case of a hydrophobic/hydrophilic pairing, vortices generated behind the hydrophilic sphere influence the air cavity development of the hydrophobic sphere. This can cause a secondary pinch-off, especially at low lateral distances. This effect becomes more pronounced at higher impact velocities. Additionally, at higher impact velocities and minimum lateral distance (direct contact between the spheres), a smaller cavity detaches from the hydrophobic sphere's cavity, attaches to the hydrophilic sphere, and moves with it. These different regimes result in varying descent velocities for the spheres.

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Section: Introductionmentioning

confidence: 99%