Proceedings of the International Conference on Coastal Engineering, No 22 (1990)



A.D. Toumazis, K. Anastasiou




A breaking wave model, which is partly physical and partly analytical, is proposed. This model is based on observations that up to a certain moment the wave presents a long, smooth, horizontal, cylindrical edge, which then segments due to surface tension effects. A disturbance on a cylindrical surface, withdrawn from the influence of gravity, becomes unstable when its wavelength exceeds the circumference of the cylinder. The rate of growth of the instability, is a function of the radius of the cylinder and the wavelength of the disturbance. Using the theory describing the evolution of the assumed hyperbolic shape of the tip of a breaking wave, the radius of the cylindrical edge is approximated to the radius of curvature of the hyperbola. The model describes the three-dimensional evolution of the curling wave crest. Scale effects are then derived which show good agreement with experimental results.