Overtopping prediction of cube and cubipod armored breakwaters using the clash neural network

Jorge Molines, Gloria Argente, Maria P. Herrera, Josep R. Medina

Monday 29 june 2015

16:15 - 16:30h at Asia (level 0)

Themes: (T) Water engineering, (ST) River and coastal engineering

Parallel session: 3E. River engineering

Van Gent et al. (2007) used most of the data from the CLASH European Project to create the CLASH neural network (hereafter CLNN). The CLNN is capable to predict wave overtopping for various structures, using 15 input parameters to define the wave conditions and structural geometry. The roughness factor (_f) is the input parameter which considers the type of armor, armor porosity and permeability of the breakwater. Bruce et al. (2006) determined roughness factors for a standard concrete armored breakwater with different type of armors, these being different from those given by the CLNN. Smolka et al. (2009) obtained a new overtopping estimator and the roughness factors for single- and double-layer Cubipod armors. In this study, using the CLNN, new roughness factors for cube and Cubipod armors were obtained to minimize the prediction error. Small-scale model tests were conducted in the wind and wave flume (30x1.2x1.2m.) at the Universitat Politècnica de València. The tested models corresponded to a conventional breakwater placed in deep water with a crown wall and without a toe berm. Three different armor configurations were tested depending on the concrete armor unit used: Cubipods in one and two layers, and cubes in two layers.. For double-layer cube armors, the CLNN gave lower mean squared error to variance (rMSE) for _f=0.50, which corresponded to the value to be used in the CLNN. However, there was a range of roughness factors in which the rMSE was almost constant, so similar overtopping predictions were obtained within this range. Overtopping discharges from cube armored breakwaters were higher than those from of single- and double-layer Cubipod armors. REFERENCES Bruce, T., Van der Meer, J.W., Franco, L., Pearson, J.M., 2006. A comparison of overtopping performance of different rubble mound breakwater armour. Proceedings 30th International Conference on Coastal Engineering. World Scientific, Vol. 5, 4567-4579. Smolka, E., Zarranz, G., Medina, J.R. 2009. Estudio Experimental del Rebase de un Dique en Talud de Cubípodos. Libro de Ponencias de las X Jornadas Españolas de Costas y Puertos, Universidad de Cantabria-Adif Congresos, 803-809. Van Gent, M.R.A., van den Boogaard, H.F.P., Pozueta, B., Medina, J.R., 2007. Neural network modelling of wave overtopping at coastal structures. Coastal Engineering 54 (8), 586–593.