WAVE REFLECTION GENERATED BY CAISSONS WITH INTERNAL RUBBLE MOUND OF VARIABLE SLOPE

Carla Faraci, Biagio Cammaroto, Luca Cavallaro, Enrico Foti

Abstract


The paper reports on an experimental campaign focused on the performances of prefabricated caissons with internal rubble mound (combined caissons) in terms of incident wave energy reduction. The frontal opening and the chamber width of the caisson were changed in order to find the optimal design dimensions allowing the reflection coefficient to be reduced as much as possible. As expected, the best performances of the combined caisson occur when the rubble mound slope is gentler. The experimental results were also compared with an analytical model available in literature; such a comparison showed that the combined caisson exhibits a smaller reflection than predicted as far as wave periods higher than 8-9 s at a prototype scale are concerned.

Keywords


rubble mound; combined caissons; reflection coefficient

References


Bennett, G.S., McIver, P., Smallerman, J.V., 1992. A mathematical model of a slotted wavescreen breakwater. Coast. Eng. 18, 231–249.http://dx.doi.org/10.1016/0378-3839(92)90021-L

Brossard, J. Jarno-Druaux, A., Marin, F., Tabel-Aoul, E.H., 2003. Fixed absorbing semi-immersed breakwater. Coastal Engineering, 49: 25-41.http://dx.doi.org/10.1016/S0378-3839(03)00044-9

Chen, X.F., Li, Y.C., 2005. Study of regular wave force on components of perforated caissons with top cover. China Offshore Platform 20 (1), 1–10.

Fugazza, M., Natale,L., 1992. Hydraulic performance of perforated breakwater. J. Waterway, Port, Coastal and Ocean Eng., 118: 1-14.http://dx.doi.org/10.1061/(ASCE)0733-950X(1992)118:1(1)

Goda, Y., Suzuki, Y., (1976). Estimation of incident and reflected waves in random wave experiments. Proc. 15th Int. Coastal Engineering Conference (ASCE), 828-845.

Isaacson, M., (1991). Measurement of regular wave reflection. J. Waterway, Port, Coastal and Ocean Eng., 117, pp. 553-569.http://dx.doi.org/10.1061/(ASCE)0733-950X(1991)117:6(553)

Jarlan, G.E.,1961. A perforated vertical wall breakwater. Dock Harbour Auth. XII, 486: 394-398.

Kondo, H. (1979). Analysis of breakwaters having two porous walls. Proc. Coastal Structures '79, 2, pp. 962-977.

Li, Y.C., Dong, G.H., Liu, H.J., Sun, D.P., 2003. The reflection of oblique incident waves by breakwaters with double-layered perforated wall. Coast. Eng. 50, 47–60.http://dx.doi.org/10.1016/j.coastaleng.2003.08.001

Liu Y., Li, Y.C., Teng B. (2007) The reflection of oblique waves by an infinite number of partially perforated caissons. Ocean Eng. 34 (2007) 1965–1976.http://dx.doi.org/10.1016/j.oceaneng.2007.03.004

Madsen, P.A. (1983) Wave reflection from a vertical permeable wave absorber. Coast. Eng. (7) pp. 381-396http://dx.doi.org/10.1016/0378-3839(83)90005-4

Mansard, E. P. D., Funke, E. R., (1980). The measurement of incident and reflected spectra using a least square method. Proc. 17th Int. Coastal Engineering Conference, (ASCE), 1, pp. 154-172.

Marks, M., Jarlan, G.E., 1968. Experimental study on a fixed perforated breakwater. Proc. 11th Coastal Engineering Conf., London, vol. 2, pp. 1121–1140.

Postma, G.M., 1989. Wave reflection from rock slopes under random wave attack. MSc. Thesis, Delft University of Technology.

Suh, K.D., Choi, J.C., Kim, B.H., Park, W.S., Lee, K.S., 2001. Reflection of irregular waves from perforated-wall caisson breakwaters. Coastal Engineering, 44: 141-151.http://dx.doi.org/10.1016/S0378-3839(01)00028-X

Suh, K.D., Park, W.S. 1995. Wave reflection from perforated wall caisson breakwaters. Coast. Eng. 26, pp. 177-193.http://dx.doi.org/10.1016/0378-3839(95)00027-5

Suh, K.D., Park, J.K., and Park, W.S. 2006. Wave reflection from partially perforated-wall caisson breakwater, Ocean Engineering, 33, 264-280.http://dx.doi.org/10.1016/j.oceaneng.2004.11.015

Sunamura and Okazaki, 1996. Breaker types and wave reflection coefficient: laboratory relationship. J. Coastal Res., 12(1): 240-245.

Takahashi, A., Yasuo, K., Fujiwara, R., Isobe, M., 2002. Performance evaluation of perforated-wall caissons by VOF numerical simulations. Proc. 28th Int. Coastal Engineering Conference (ASCE), 1364-1376.

Thorton, E. B., Calhoun, R. J., (1972). Spectral resolution of breakwater reflected waves". Proc. ASCE 98 (WW4), pp. 443-460.

Zhu, S., Chwang, A.T. (2002), Experimental studies on caisson-type porous seawalls. Experiments in Fluids 33 512–515


Full Text: PDF

Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.