CFD Simulations of the Propagation of Free-Surface Waves Past Two Side-By-Side Fixed Squares with a Narrow Gap

Abstract

Two-dimensional computational fluid dynamics (CFD) simulations are carried out to investigate the gap resonance phenomenon that occurs when free-surface waves travel past twin squares in tandem. The volume of fluid method is used to capture the free surface. Validation studies of the present numerical model are conducted for different incident wave frequencies. The numerical results agree well with the published experimental data in terms of the free surface elevations in the gap. The hydrodynamic characteristics of the water column in the gap are investigated at different incident wave frequencies and gap widths. It is found that the free surface elevation in the gap increases and then decreases with the increasing incident wave frequency. The horizontal force on the weather side square structure (the structure in front of the gap) reaches the peak value at a larger frequency than the gap resonance frequency, whereas the variation of the horizontal force on the lee side structure (the structure behind the gap) is in-phase with the free surface elevation in the gap. Moreover, the added mass of the water column in the gap increases with the increasing gap width, which results in the decrease of resonance amplitude and frequency in the gap. However, this does not necessarily reduce the peak value of the horizontal forces on the structures.

The Effect of Draft Ratio of Side-By-Side Barges on Fluid Oscillation in Narrow Gap

“…In set 1, the draft ratio of the floating body is 1. We compared the calculation results of set 1 with Saitho's [5] experimental data and others' calculation results [18], as shown in Figure 6. It shows that the results of set 1 are in good agreement with the experimental results and others' data.…”

“…This work aims to explore the effect of barge draft on the gap resonant response amplitude and resonant frequency, illustrate the damping mechanism at the gap resonance and investigate the effect of the floating body draft on the flow structures and energy dissipation around two 2D side-by-side barges. Following the argumentation of Zhang et al [18] that turbulent dissipation does not play a significant role as far as wave damping in the narrow gap problem is concerned, laminar CFD simulations are performed in a 2D wave tank by coupling the Waves2Foam package with the code OpenFOAM in the present study, and the Volume of Fluid (VOF) model is used to capture the free surface wave during the simulation.…”