Probabilistic analysis of irregular wave runup on a fixed and truncated surface-piercing vertical cylinder: Fid-Bau Portal

Probabilistic analysis of irregular wave runup on a fixed and truncated surface-piercing vertical cylinder

Cao, Deping / Chen, Hao

Abstract This paper presents a numerical and experimental study on irregular wave runup on a fixed and truncated surface-piercing vertical cylinder. The numerical model was set up based on the incompressible two-phase flow solver in the open-source toolbox OpenFOAM. The model was successfully validated against the experimental data on both regular and irregular incident wave and wave runup. We analyse the characteristics of the runup spectrum against different $k_{p} H_{s}$ and $k_{p} D$ , where $k_{p}$ is the wave number at peak frequency, $H_{s}$ is the significant wave height and $D$ is the diameter of the cylinder. A new method is proposed to predict the distribution of runup height. In this method, the average height of the highest one-third of all wave runup $R_{1 / 3}$ is calculated based on the expansion of an empirical formula proposed in Cao et al., (2017). Then the non-dimensional runup height $R / R_{1 / 3}$ is fitted into a two-parameter Weibull distribution, where the shape parameter and scale parameter are provided as a function of $k_{p} H_{s}$ and $k_{p} D$ based on the interpolation of the experimental and numerical data. Based on the fitted Weibull distribution, the runup height at any cumulative probability can be determined. This newly proposed method is validated against the numerical and experimental data on the 2% excess wave runup height $R_{2 %}$ , and the deviations are found to be within $\pm 15 %$ for most of the cases. Finally, a sensitivity analysis is conducted to demonstrate that the model uncertainty is within 15%.

Highlights • The present paper proposes a new method to evaluate irregular wave runup on a cylinder. • A spectrum analysis was conducted to investigate the effects of wave steepness and scattering parameter on the runup spectrum. • A probabilistic analysis was conducted to fit wave runup into a two-parameter Weibull distribution. • Sensitivity analysis shows that the model uncertainty is within 15%.