The understanding of transient wave dynamics spectra on solid and/or permeable structures is of paramount importance for manufacturing and designing new material for the next generation of coastal defences in the UK. The observed sea rises and more frequent severe storms due to climate change are exposing our coastal defences to serious damage, induced casualties and huge economic costs. The rigorous simulation of the dynamics of the flow prior to, at and after impact at complex structures and the understanding of their response in a more systematic way needs to be investigated. However, this represents a great fluid dynamics simulation with intensive computations as the structure of the porous medium gets complex. In this PhD work, free surface flow simulations, analyses of forces of impact, and the integrity and responses of structures to transient impulsive signals with compressed air bubbles will be investigated. Distributed computing intensive simulations will be achieved to discover optimised designs of resilient porous structures of the future.