Author(s): Eugenio Pugliesecarratelli; Fabio Dentale; Giovanna Donnarumma; Rosaria Ester Musumeci
Linked Author(s):
Keywords: Numerical Simulation of Waves; Breakwaters; Run Up; Reflection; Rubble Mound
Abstract: The paper provides some developments of a numerical approach (“Numerical Calculation of Flow Within Armour Units”, FWAU) to the design of rubble mound breakwaters. The hydrodynamics of wave induced flow within the interstices of concrete blocks is simulated by making use of advanced, but well tested, Computational Fluid Dynamics (CFD) techniques to integrate Reynolds Averaged NavierStokes equations. The structure is numerically modeled by overlapping individual three-dimensional elements and a fine computational grid is fitted so as to provide enough computational nodes within the flow paths. While computationally very heavy, FWAU is gaining ground (Xiang et al., 2012), (Altomare et al., 2012) due to its obvious advantages over the “porous media" seeping flow approach currently used in maritime CFD engineering practice, i. e. the possibility of accounting for the highly non stationary effects, the reducedneed of ad hoc calibration of filtration parameters andalso – in perspective – the evaluation of hydrodynamic forces on single blocks. FWAU however is not yet a fully mature technique, and in order to turn it into a practical design tool, a number of difficulties have to be overcome. In the first place a computational procedure has to be developed to allow for the construction of the virtual breakwater from a database of block shapes; in the second place, enough evidence has to be collected or produced to validate FWAU against experimental results. While the first aspect has been accomplished by making use of current Computer Assisted Design (CAD) software, validation is still an open problem, since dynamical parameters within the blocks cannot be easily measured. A wealth of experimental results is however available on parameters such as run-up, reflection and global stability of rock mounds; the paper presentsrecentresultsabout this validation, as well as insight into fluid dynamical aspects.
Year: 2013