Simulation of the Dynamic Effects of Wave Slamming on Flexible Marine Structures

Abstract

Flexible marine structures such as open piled jetties, which are comprised of a deck supported on piles, are commonly used in coastal areas around the world. Due to certain conditions, these structures are sometimes exposed to direct wave attack, in which the deck is exposed to vertical slamming load, possibly causing extensive local and global damage. Wave slamming is a complex phenomenon influenced by several parameters making it difficult to predict or quantify. Effects of wave slamming on flexible marine structures were investigated in three stages. Stage I included a review of a 3D physical modelling study conducted by a specialized company to investigate wave loading on a piled jetty structure located on the coastline of Dubai, UAE. Stage Ⅱ included a wave load prediction based on parametric equations. Stage Ⅲ included computational fluid dynamics (CFD) numerical modelling of the same jetty structure from StageⅠandⅡusing DualSPHysics software, which is based on smoothed particle hydrodynamics (SPH). Stage Ⅲ was divided into three phases. Phase 1 comprised of calibrating the CFD model against the physical modelling study by replicating the physical model setup and wave conditions in DualSPHysics. Phase 2 comprised of a sensitivity analysis for the inter-particle distance parameter in DualSPHysics, which represents the numerical model’s resolution and determines the required computational and storage demands of each simulation. Five inter-particle distances were investigated in Phase 2 with 0.005m selected as the suitable inter-particle distance to be used in Phase 3. Phase 3 comprised of simulating three relative wave parameters: (a) Relative Clearance (Δh /Hs), (b) Relative Wave Height (Hs / h), and (c) Relative Deck Width (B / λ). For each relative wave parameter, five different values were simulated to investigate their effect on the wave pressure imposed on the jetty. A control simulation was initially developed, which was then used as the base case for all the subsequent simulations. Wave pressure distributions were plotted for each simulation and the maximum pressures were compared to determine the trends caused by the varying parameters. Finally, results from the three stages were compared and recommendations were provided on the suitability of each method for the design of flexible marine structures.