## 1 Introduction
In their study, the largest wave force was observed when the pile was located at 3/4 R (R is the maximum run-up height) below the shoreline. [PERSON] et al. [10] studied breaking wave impact forces on the vertical cylinder and the inclined cylinder which direction is parallel to the wave propagation using modified Navier-Stokes equations. The effect on the breaking wave forces due to the vibration of cylinders in the experiment was studied. The computed breaking wave forces were in good agreement with the experimental data filtered by an FFT low-pass filter and EMD. [PERSON] et al. [11] and [PERSON] et al. [12] studied the influence of wave breaking locations on the interactions between breaking waves and a vertical cylinder using the \(k-\omega\) turbulence model. They pointed out that the largest total horizontal wave force was generated when the overturning wave tongue was just below the wave crest level and hit the cylinder. [PERSON] and [PERSON] [13] investigated the slamming coefficients on the local cylindrical members of a jacket structure under plunging breakers by solving Navier-Stokes equations together with the VOF method. It was found that the maximum slamming coefficients increase first and then decrease in the impact area, and the curves presented triangular shapes. It is recommended that when calculating the slamming force on the offshore wind turbine substructures, a triangular distribution of force should be adopted instead of using the maximum value of slamming force along the entire member. Recently, [PERSON] et al. [14; 15] employed the \(k-\omega\)_SST_ turbulence model with the VOF method to study the higher-harmonic force on a vertical cylinder under the breaking wave impact. The numerical results show that the occurrence of the secondary load cycles was related to the Froude number and the wave steepness. Both slamming wave force and secondary load can generate the higher-harmonic wave force in the case of breaking wave. Based on a review of the literature, most studies focused on the effects of wave steepness, wave breaking location, and different numerical models. Only a few papers investigated the influence of inclined angles of the cylinder parallel to the direction of wave propagation. However, for assessment on the stability and safety of the structures during the engineering design process, it is important to understand the interaction between the breaking waves and the cylinders with different inclined directions. Therefore, the primary purpose of the present study is to investigate the characteristics of breaking wave forces on a standing cylinder with different transverse inclined angles in orientation normal to the wave propagation. In this paper, URANS equations are solved by using an open-source CFD software Open FOAM. The interface between air and water is captured using the VOF method. This paper is structured as follows. First, the convergence studies on the grid and time-step are presented. Then numerical results of total horizontal breaking wave forces on the cylinder and free surface elevations are compared with the published experimental data to validate the accuracy of the numerical model. Furthermore, the characteristics of the free surface elevations and different compositions of wave forces are studied. The effects of the transverse inclined angle are discussed in detail. Finally, the conclusions based on the present numerical results are summarized.