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Main Authors: Turczynowicz, Jan, Waszkiewicz, Radost, Gładczuk, Łukasz
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2312.13099
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author Turczynowicz, Jan
Waszkiewicz, Radost
Gładczuk, Łukasz
author_facet Turczynowicz, Jan
Waszkiewicz, Radost
Gładczuk, Łukasz
contents Although it is commonly expected that a metal disk placed on the surface of water will sink, our investigation has revealed a surprising phenomenon: a vertical jet directed onto the disk from above can allow it to remain afloat. This result defies intuition, as one would assume that the force of the jet's impact would cause the disk to sink. We have discovered that this phenomenon occurs as a result of water displacement from the top of the disk caused by the impacting jet, operating through a mechanism similar to the hydraulic jump. This displacement increases the effective immersed volume, resulting in an increased buoyant force that balances gravity. In contrast to the classical case, here the jump radius is fixed by the geometric parameters of a disk, a phenomenon we refer to as the boundary jump. To further explore this effect, we have presented a theoretical model based on scaling laws, which provides the conditions required for the disk to float. The prefactor was determined through an independent experiment. Finally, we conducted experiments on the disk's floating and sinking, which showed a good match with the proposed theory.
format Preprint
id arxiv_https___arxiv_org_abs_2312_13099
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Preventing sinking of a disk by leveraging the boundary jump phenomenon
Turczynowicz, Jan
Waszkiewicz, Radost
Gładczuk, Łukasz
Fluid Dynamics
Although it is commonly expected that a metal disk placed on the surface of water will sink, our investigation has revealed a surprising phenomenon: a vertical jet directed onto the disk from above can allow it to remain afloat. This result defies intuition, as one would assume that the force of the jet's impact would cause the disk to sink. We have discovered that this phenomenon occurs as a result of water displacement from the top of the disk caused by the impacting jet, operating through a mechanism similar to the hydraulic jump. This displacement increases the effective immersed volume, resulting in an increased buoyant force that balances gravity. In contrast to the classical case, here the jump radius is fixed by the geometric parameters of a disk, a phenomenon we refer to as the boundary jump. To further explore this effect, we have presented a theoretical model based on scaling laws, which provides the conditions required for the disk to float. The prefactor was determined through an independent experiment. Finally, we conducted experiments on the disk's floating and sinking, which showed a good match with the proposed theory.
title Preventing sinking of a disk by leveraging the boundary jump phenomenon
topic Fluid Dynamics
url https://arxiv.org/abs/2312.13099