Wave Loads Assessment on Coastal Structures at Inundation Risk Using CFD Modelling

Abstract

AbstractOver the past few decades, extreme phenomena have raised concern due to their severity and increasing risks to inhabitants, infrastructures, and anthropic activities. Nowadays, coastal structures overtopping, beaches erosion and destruction of infrastructures are common along the coasts around the world. It is of crucial importance to anticipate those impacts in order to efficiently contribute to their mitigation and adopt efficient defense measures. In a previous experimental work based on a large-scale physical model, the relationship between the air gap of an elevated coastal structure on top of wooden piers and the resulting horizontal and vertical wave forces were studied for different wave load conditions. These experimental results serve as calibration data for a numerical model to simulate the fluid/structure interaction, using CFD tools. Three scenarios were simulated with different heights of the air gap between the water and the structure base levels, for a given wave condition. When the numerical results are compared with the physical model results, the maximum values of the horizontal and vertical forces, obtained numerically are satisfactory, with an average relative difference of 14.4% and 25.4%, respectively. In addition, a numerical model at full scale was applied, to simulate the pressures and shear stresses that act on the piers that support the structure, considering different heights of the air gap and assessing the respective CPU simulation times. This way the operational modelling capabilities of the CFD model were assessed to determine the forecast leading time restrictions for eventual use within an early warning system.KeywordsCoastal riskElevated coastal structureNumerical simulationFlow-3D®