Author(s): F. Federico; C. Cesali
Linked Author(s):
Keywords: Fluid-structure interaction; Impact; Numerical simulation; Hydrodynamic pressure; Impulsive phase
Abstract: The initial, impulsive, phase of the impact of fluids against structures is analytically and numerically modelled by taking into account different geometrical configurations of the interacting bodies, as well as the properties of the involved materials. A review of technical literature regarding impact shows that a modified value of the hydrodynamic pressure exerted by an incompressible fluid (proportional to the square of velocity), or a multiple of the hydrostatic force, are usually considered in the design criteria applied to estimate the impact force acted by a fluid-like flow against a structure. By this way, the impact force assumes a constant value. Recent theoretical and experimental studies, mainly developed in the field of coastal engineering, reveal that these simplified criteria are not supported by rational presumptions; furthermore, the dynamic actions arising during the initial, impulsive, phase of the impact phenomenon are neglected. Geometrical (e.g. wave shape, both depth and width), kinematic (e.g. impact velocity), physical and mechanical (e.g. presence of air in the fluid, solid concentration, fluid viscosity) variables control the impact phenomenon; their role must be carefully evaluated to identify the actions which determine ultimate limit states of the structures under impact, and to determine their evolution along time to distinguish the effects related to the impulsive phase from those ones related to the hydrodynamic phase. To this purpose, numerical (FE) analyses of the dynamic interaction “fluid-like flow - structure” during impact have been carried out; their results allow to highlight the role played by the fluid’s speed, the density and the compressibility of the involved materials, on which the impact force, as well as the duration of impact, depend.
DOI: https://doi.org/10.3850/978-981-11-2731-1_079-cd
Year: 2018