Numerical analysis of a regular wave over a vertical pile with a square section

Abstract

The study of the action of waves on piles is very important for the design of structures in coastal and oceanic areas. Currently, there is strong interest in analyzing the action of waves on piles with non-circular sections, such as rectangular or square ones. According to Vengatesan et al. (2000), the main reason for this interest is the low cost of the connections of the members in the structures with these sections. The objective of this paper is to analyze the action of a regular wave on a vertical pile with a square section employing two differents numerical methodologies for prediction of the wave fluid dynamic. To achieve this goal were used the FLUINCO and FLUENT® softwares. FLUINCO (Teixeira, 2001) employs a partitioned two-step semi-implicit Taylor-Galerkin method in the Navier-Stokes equations. The free surface is governed by its kinematic boundary condition and an arbitrary Lagrangian-Eulerian (ALE) formulation is used to enable movements of the free surface. The FLUENT® code (2006), version 6.3.26, implements a finite volume technique to solve the equation of continuity and the Navier-Stokes equations. The free surface is described by using the VOF method (Volume Of Fluid). The wave period of the studied problem is 4s and its height is 0.05 m. The pile is seated on the bottom and located in the center of a channel. The dimensions of the pile section are 1m × 1m and the channel is 30m long, 10m wide and 1m deep. This paper shows the results obtained by the models in terms of the velocity vectors, the deformation of the free surface and the drag force caused by the wave on the pile. The total horizontal force acting on the pile was analytically calculated using the Morison equation. It was observed very similar results to the numerical ones.