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Experimental study on oblique water entry of two tandem spheres with collision effect

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Abstract

In this paper, the hydrodynamic characteristics associated with oblique water entry of two tandem spheres were experimentally investigated using high-speed photography. The results indicated that in the cavity formed by the first sphere, a suction effect due to the pressure difference between inside and outside the cavity was developed, which consequently led the second sphere to accelerate when it was totally submerged in the cavity. In addition, the first sphere was accelerated with a sudden expansion of the cavity radius due to the energy transfer effect associated with the collision of the two spheres, with a ring joint geometry observed, and the cavity finally broke up into two sections. Since the second sphere moved inside the cavity with less drag, it finally reached the first sphere and a second collision event was observed.

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Acknowledgements

This work was financially supported by the National Natural Science Foundation of China (NSFC) under Project Number of 51609115 and 11702173, Fundamental Research Funds for the Central Universities under Project Number of 30918012201 and 30917012101, Key Laboratory Fund under Project Number of 614260403040317 and 614260403041803, and Open Fund of State Key Laboratory of Ocean Engineering under Project Number of 1818.

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Correspondence to Xujian Lyu or Zhaoyu Wei.

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Yun, H., Lyu, X. & Wei, Z. Experimental study on oblique water entry of two tandem spheres with collision effect. J Vis 23, 49–59 (2020). https://doi.org/10.1007/s12650-019-00602-4

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Keywords

  • Tandem spheres
  • Oblique water entry
  • Collision