Numerical investigation of wave actions on two side by side boxes in close proximity using IMLPG_R method

Abstract

The capability of the Meshless Local Petrov Galerkin method to understand the gap resonance between two side-by-side fixed boxes in close proximity is reported in this study. The present paper focuses on bilge-shaped boxes, the draft of the downstream box, and various hydrodynamic aspects of the gap resonance problem. Both regular wave and focused wave are used in this study. The piston mode resonance frequencies for different model configurations are determined by conducting regular wave tests within the range of 0.625 Hz to 1.54 Hz. The effect of wave steepness is also discussed. Near the resonance frequency, the model configuration having round bilge shapes showed a 77% increase in wave amplification when compared to square bilge shape. Similarly, horizontal and vertical forces on boxes also showed a significant increase in the case of round bilge configuration. For the different model configurations tested, an increase in the draft of the downstream body is found to amplify free surface elevation in the gap by 19% near gap resonance frequency. The reasons for various distinctive behavior for wave amplification inside the narrow gap and force acting on the boxes are explained with the help of instantaneous velocity and vorticity from the numerical simulation. The paper also discusses the water column in the narrow gap excited with a focused transient wave group. A four-phase combination method is then used to extract the first-order and higher-order harmonics of free surface elevation in the narrow gap and the forces acting on the boxes to analyze the influence.