Citation:

Mohammad Hassan and Swaroop Nandan Bora.Exciting Forces for a Wave Energy Device Consisting of a Pair of Coaxial Cylinders in Water of Finite Depth[J].Journal of Marine Science and Application,2013,(3):315-324.[doi:10.1007/s11804-013-1207-9]

Click and Copy
Mohammad Hassan and Swaroop Nandan Bora.Exciting Forces for a Wave Energy Device Consisting of a Pair of Coaxial Cylinders in Water of Finite Depth[J].Journal of Marine Science and Application,2013,(3):315-324.[doi:10.1007/s11804-013-1207-9]

Exciting Forces for a Wave Energy Device Consisting of a Pair of Coaxial Cylinders in Water of Finite Depth

- Title:
- Exciting Forces for a Wave Energy Device Consisting of a Pair of Coaxial Cylinders in Water of Finite Depth

- Author(s):
- Mohammad Hassan and Swaroop Nandan Bora

- Affilations:

- Keywords:
- diffraction; finite depth; virtual boundary; exciting force; wave energy device; coaxial cylinder

- DOI:
- 10.1007/s11804-013-1207-9

- Abstract:
- Two coaxial vertical cylinders one is a riding hollow cylinder and the other a solid cylinder of greater radius at some distance above an impermeable horizontal bottom, were considered. This problem of diffraction by these two cylinders, which were considered as idealization of a buoy and a circular plate, can be considered as a wave energy device. The wave energy that is created and transferred by this device can be appropriately used in many applications in lieu of conventional energy. Method of separation of variables was used to obtain the analytical expressions for the diffracted potentials in four clearly identified regions. By applying the appropriate matching conditions along the three virtual boundaries between the regions, a system of linear equations was obtained, which was solved for the unknown coefficients. The potentials allowed us to obtain the exciting forces acting on both cylinders. Sets of exciting forces were obtained for different radii of the cylinders and for different gaps between the cylinders. It was observed that changes in radius and the gap had significant effect on the forces. It was found that mostly the exciting forces were significant only at lower frequencies. The exciting forces almost vanished at higher frequencies. The problem was also investigated for the base case of no plate arrangement, i.e., the case having only the floating cylinder tethered to the sea-bed. Comparison of forces for both arrangements was carried out. In order to take care of the radiation of the cylinders due to surge motion, the corresponding added mass and the damping coefficients for both cylinders were also computed. All the results were depicted graphically and compared with available results.

Abramowitz M, Stegun IA (1965). Handbook of mathematical functions. Dover, New York.

Bhatta DD, Rahman M (2003). On the scattering and radiation problem for a cylinder in water of finite depth. International Journal of Engineering Science, 41, 931-967.

Bhattacharjee J, Soares CG (2010). Wave interaction with a floating rectangular box near a vertical wall with step type bottom topography. Journal of Hydrodynamics, 22(5), 91-96.

Garrett CJR (1971). Wave forces on a circular dock. Journal of Fluid Mechanics, 46, 129-139.

Hassan M, Bora SN (2012). Exciting forces for a pair of coaxial hollow cylinder and bottom-mounted cylinder in water of finite depth. Ocean Engineering, 50, 38-43.

MacCamy RC, Fuchs RA (1954). Wave forces on piles: A diffraction theory. Technical Memo, No. 69, US Army Beach Erosion Board.

Rahman M, Bhatta DD (1993). Second order wave forces on a pair of cylinders. Canadian Applied Mathematics Quarterly. 1(3), 343-382.

Shen YM, Zhang YH, You YG (2005). On the radiation and diffraction of linear water waves by a rectangular structure over a sill. Part I. Infinite domain of finite water depth. Ocean Engineering, 32, 1073-1097.

Siddorn P, Taylor RE (2008). Diffraction and independent radiation by an array of floating cylinders. Ocean Engineering, 35, 1289-1303.

Vicente PC, Falcão AFO, Justino PAP (2011). Optimization of mooring configuration parameters of floating wave energy converters. Proceedings of the ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering (OMAE2011), Rotterdam, the Netherlands, OMAE2011-49955.

Wu BJ, Zhang YH, You YG, Jie DS, Chen Y (2006). On diffraction and radiation problem for two cylinders in water of finite depth. Ocean Engineering, 33, 679-704.

Wu BJ, Zhang YM, You YG, Sun XY, Chen Y (2004). On diffraction and radiation problem for a cylinder over a caisson in water of finite depth. International Journal of Engineering Science, 42, 1193-1213.

Zhang YH, Shen YM, You YG, Wu BJ, Rong Liu (2005). Hydrodynamic properties of two vertical truncated cylinders in waves. Ocean Engineering, 32, 241-271.

Zhu SP, Mitchell L (2009). Diffraction of ocean waves around a hollow cylindrical shell structure. Wave Motion, 46, 78-88.

- Memo:
- -

Last Update:
2013-08-27