Dogan Kisacik, Peter Troch


Vertical breakwaters and sea walls are frequently used structures to protect ports from sea actions like waves and high water levels. Vertical structures expose slowly-acting pulsating loads or more intense but shorter lasting impulsive loads. Prediction methods for wave loads to calculate hydraulic responses of these structures generally use the incident significant wave height, often defined in the water depth at the seaward toe of the structure (h_s). Where, wave breaking has significant influence on design wave heights. In addition, due to the result of the reflection or/and turbulence left from preceding waves, the inception of wave breaking point is different than the point in the case without vertical structures. Therefore, the hydraulic performance of load tests on vertical structures should be known.
The reflection coefficients C_r, measured at the toe of the foreshore, are categorized based on the breaker shapes. According to the results, C_r values between, 0.55-0.80, and 0.45-0.70 are found for breaker types BWSAT (breaking with small air trap) and BWLAT (breaking with large trap) respectively.
The margin between non-braking and breaking waves is considered as the inception point of breaking. This point is compared with the breaking point for the measurements without the scaled model to determine the influence of the scaled model on the inception point of the wave breaking. It is seen that the existence of the model postpones the inception of wave breaking for some waves which would normally break without the presence of the scaled model.
The main objective of the present research is to improve methods to predict wave behavior and breaker heights for increasing safety of structures constructed in the surf zone. In this particular research, small scale model tests were carried out to fulfill the above goals.


Wave breaking, wave reflection, wave shoaling and vertical structures

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Allsop, W., 1999, “Reflection coefficients", Probabilistic design tool for the vertical walls, volume IIa – Hydraulic aspects, pp 13

Battjes, J. A., 1974, "A Computation of Set-Up, Longshore Currents, Run-Up and Overtopping Due to Wind-Generated Waves," Ph.D. diss., Delft University of Technology, The Netherlands

Camenen B., Larson, M. (2007), Predictive Formulas for Breaker Depth Index and Breaker Type,-Journal of Coastal Research-2007-Vol-23-Issue-4-pp-1028-1041

Galvin, C.J., Jr., (1968), Breaker Type Classification on Three Laboratory Beaches, Jour. Geophys. Res., 73(12), 3651,

Goda, Y., 1970. A synthesis of breaker indices. Transactions of Japan Society of Civil Engineers 2, 39–49.

Goda, Y., 1975. Irregular wave deformation in the surf zone. Coastal Engineering in Japan 18, 13–26.

Goda, Y., 2010. “Reanalysis of regular and random breaking wave statistics”. Coastal Engineering Journal 52 (1), 71–106.

Kisacik, D.; Troch, P.; Van Bogaert, P., 2012, “Description of loading conditions due to violent wave impacts on a vertical structure with an overhanging horizontal cantilever slab”, Coastal Engineering, Volume 60, Issue 1, February 2012, Pages 201-226

Mansard, E. P. D., Funke, E. R., (1980),Measurement of incident and reflected spectra using a least squares method, -National Conference Publication-Institution of Engineers-n-80/1-pp-95-96

McCowan, J. [1894] “On the highest waves in water,” Phil. Mag. Ser. 5, 36: 351-358.

Miche, R. (1944). Mouvements ondulatoires de la mer en profondeur constante ou decroissante, Annales des Ponts et Chaussees, Vol. 114, 25–78, 131–164, 270–292, 369–406 (in French).

Michell, J.H., 1893. On the highest waves in water. Philosophical Magazine 36, 430–435 Ser. 5.

Munk, W.H., 1949. “The solitary wave theory and its applications to surf problems”. Annals of the New York Academy of Sciences 51, 376–462.

Rattanapitikon, W., T. Vivattanasirisak and T. Shibayama, (2003) A Proposal of New Breaker Height Formula, Coastal-Engineering-Journal-2003-Volume-45-no-1-pp-29-48

Sawaragi, T. and K.Iwata (1973), Some Considerations on Hydraulic Characteristic of perforated breakwater Quay, Proc. J. S. C. E. No 220

Southgate, H.N., 1995. “Prediction of wave breaking processes at the coastline”. In: Rahman, M., Editor, , 1995. Advances in Fluid Mechanics vol. 6, Computational Mechanics Publications, Southampton, UK.

Yamada, H., Kimura, G. and Okabe, J. [1968] “Precise determination of the solitary waves of extreme height on water of a uniform depth,” Rep. Res. Inst. Applied Mech., Kyushu Univ. XVI (52): 15-32.

Yoo, D. (1986), Mathematical modelling of wave-current interacted flow in shallow waters, University of Manchester,

Yu Liu, Xiaojing Niu, Xiping Yu, 2011 “A new predictive formula for inception of regular wave breaking”, Coastal Engineering, Volume 58, Issue 9, September 2011, Pages 877-889