Extracting the Solution of Three-Dimensional Wave Diffraction Problem from Two-Dimensional Analysis by Introducing an Artificial Neural Network for Floating Objects

Abstract

The diffraction of the waves from the two ends of floating breakwaters (FBWs) that have limited length, are practically a three-dimensional (3D). In order to perform a two-dimensional vertical (2DV) analysis to solve the wave diffraction problem, some "correcting factors" are required to modify the 2DV results and make them comparable and verifiable against 3D solutions. The main objective of the current study is to propose a method to obtain these correcting factors and demonstrate its usefulness through some example cases. An Artificial Neural Network (ANN) is trained by three main non-dimensional independent variables to predict the mentioned factors. In order to set up the ANN, a database including both 2DV and 3D results is required. The 2DV results are obtained by employing a semi-analytical method, namely the Scaled Boundary Finite Element Method (SBFEM). A basic change in the location of the scaling center is implemented. The 3D results are obtained via ANSYS AQWA software. Eighty-one cases are simulated on a floating object with rectangular cross-sections. The correlation factor 0.9607 R  for a group of new samples shows that the predicted results are closely matched to the target values. The correcting factor applies the 3D effects of diffracted waves around the structures on 2DV results and produces a more accurate prediction.

Solving Wave Interaction with a Floating Breakwater in Finite Water Depth Using Scaled Boundary FEM

“…Thus,  changes from zero at the interface boundaries int1 As reported by Fouladi et al [13], the governing equations in the modified SBFEM coordinate system can be expressed as follows:…”

“…During past decades, many researchers have carried out numerical and experimental studies to investigate the wave interaction with FBWs [5][6][7][8][9][10][11]. Among different numerical approaches, the Scaled Boundary Finite Element Method (SBFEM) has been developed, perfected and extended in recent years to analyze the interactive systems in an infinite solution domain [12][13][14][15][16][17]. The SBFEM is a novel and emerging semi-analytical method developed by Wolf in the elasto-statics and elastodynamics areas that combines the advantages of both the finite element and the boundary element methods [18].…”

“…The results demonstrate that the proposed method by Fouladi et al [12] can be extended efficiently to solve wave interaction problems with FBW having other types of cross sections, resulting in direct engineering applications. As outlined in detail by Fouladi et al [13], in the proposed model, the scaling centers of the bounded sub-domains are located within the associated solution domain, leading to the homogenization of the governing equations in the scaled boundary coordinate systems, and thus eliminating the need for organizing different forms of particular solutions. "This study aims to develop an efficient and accurate analytical model to analyze full interaction between seawater waves and cylindrical floating breakwaters in an infinite fluid domain of finite arbitrary water depth.…”