Finite Element Model for Laplace Equation

Article Preview

Abstract:

The mild-slope equation has widely been used for calculation of shallow water wave transformation. Recently, its extended version was introduced, which is capable of modeling wave transformation on rapidly varying topography. These equations were derived by integrating the Laplace equation vertically. Here, we develop a finite element model to solve the Laplace equation directly while keeping the same computational efficiency as the mild-slope equation. This model assumes the vertical variation of the wave potential as a cosine hyperbolic function as done in the derivation of the mild-slope equation, and the Galerkin method is used to discretize it. The computational domain is discretized with proper finite elements, while the radiation condition at infinity is treated by introducing the concept of an infinite element. The upper boundary condition can be either free surface or a solid structure. The applicability of the developed model is verified through example analyses of two-dimensional wave reflection and transmission. Analysis is also made for the case where a solid structure is floated near the still water level.

You might also be interested in these eBooks

Info:

Periodical:

Pages:

9-12

Citation:

Online since:

December 2012

Export:

Price:

Permissions CCC:

Permissions PLS:

Сopyright:

© 2013 Trans Tech Publications Ltd. All Rights Reserved

Share:

Citation:

[1] J. C. W. Berkhoff, Computation of combined refraction-diffraction, in: Proc. 13th Coastal Eng. Conf., Vancouver, Vol. 1 (1972) pp.471-490.

Google Scholar

[2] S. R. Massel, Extended refraction-diffraction equation for surface waves, Coastal Eng. Vol. 19 (1993) pp.97-126.

DOI: 10.1016/0378-3839(93)90020-9

Google Scholar

[3] P. G. Chamberlain and D. Porter, The modified mild-slope equation, J. of Fluid Mech. Vol. 291 (1995) pp.393-407.

DOI: 10.1017/s0022112095002758

Google Scholar

[4] K. D. Suh, C. H. Lee and W. S. Park, Time-dependent equations for wave propagation on rapidly varying topography, Coastal Eng. Vol. 32 (1997) pp.91-117.

DOI: 10.1016/s0378-3839(97)81745-0

Google Scholar

[5] J. R. Houston, Combined refraction and diffraction of short waves using the finite element method, Applied Ocean Research. Vol. 3 (1981) pp.163-170.

DOI: 10.1016/0141-1187(81)90058-4

Google Scholar

[6] A. G. Davies and A. D. Heathershaw, Surface-wave propagation over sinusoidally varying topography, J. of Fluid Mech. Vol. 144 (1984) pp.419-443.

DOI: 10.1017/s0022112084001671

Google Scholar

[7] C. H. Lee, W. S. Park, Y. S. Cho and K.D. Suh, Hyperbolic mild-slope equations extended to account for rapidly varying topography, Coastal Eng. Vol. 34 (1998) pp.243-257.

DOI: 10.1016/s0378-3839(98)00028-3

Google Scholar