Wind and Structures

Techno-Press (테크노프레스)
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Hydrodynamic forces on blocks and vertical wall on a step bottom

  • Mondal, Ramnarayan (Institute for Turbulence-Noise-Vibration Interaction and Control Harbin Institute of Technology) ;
  • Alam, Md. Mahbub (Institute for Turbulence-Noise-Vibration Interaction and Control Harbin Institute of Technology)
  • Received : 2019.09.12
  • Accepted : 2020.01.26
  • Published : 2020.05.25
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Abstract

A study, using potential water wave theory, is conducted on the oblique water wave motion over two fixed submerged rectangular blocks (breakwaters) placed over a finite step bottom. We have considered infinite and semi-infinite fluid domains. In both domains, the Fourier expansion method is employed to obtain the velocity potentials explicitly in terms of the infinite Fourier series. The unknown coefficients appearing in the velocity potentials are determined by the eigenfunction expansion matching method at the interfaces. The derived velocity potentials are used to compute the hydrodynamic horizontal and vertical forces acting on the submerged blocks for different values of block thickness, gap spacing between the two blocks, and submergence depth of the upper block from the mean free surface. In addition, the wave load on the vertical wall is computed in the case of the semi-infinite fluid domain for different values of blocks width and the incident wave angle. It is observed that the amplitudes of hydrodynamic forces are negligible for larger values of the wavenumber. Furthermore, the upper block experiences a higher hydrodynamic force than the lower block, regardless of the gap spacing, submergence depth, and block thickness.

Keywords

Acknowledgement

The authors wish to acknowledge the support given to them from National Science Foundation of China through grants 11672096 and 91752112 and from Research Grant Council of Shenzhen Government through grant JCYJ2018 0306171921088.

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