Journal of Marine Science and Application

, Volume 16, Issue 4, pp 480–489

# Wave analysis of porous geometry with linear resistance law

• Jørgen Dokken
• John Grue
• Lars Petter Karstensen
Article

## Abstract

The wave diffraction-radiation problem of a porous geometry of arbitrary shape located in the free surface of a fluid is formulated by a set of integral equations, assuming a linear resistance law at the geometry. The linear forces, the energy relation and the mean horizontal drift force are evaluated for non-porous and porous geometries. A geometry of large porosity has an almost vanishing added mass. The exciting forces are a factor of 5–20 smaller compared to a solid geometry. In the long wave regime, the porous geometry significantly enhances both the damping and the mean drift force, where the latter grows linearly with the wavenumber. The calculated mean drift force on a porous hemisphere and a vertical truncated cylinder, relevant to the construction of fish cages, is compared to available published results.

## Keywords

wave analysis fish cages mean drift force wave exciting force added mass damping

## Notes

### Acknowledgements

The wave radiation-diffraction program WAMIT (version 5.3) was provided by Massachusetts Institute of Technology and Det Norske Veritas (now DNV-GL) through a mutual agreement with University of Oslo in 1994.

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© Harbin Engineering University and Springer-Verlag GmbH Germany 2017

## Authors and Affiliations

• Jørgen Dokken
• 1
• John Grue
• 1
• Lars Petter Karstensen
• 1
1. 1.Mechanics Division, Department of MathematicsUniversity of OsloOsloNorway