Application of Genetic Algorithm for Optimum Hydrodynamic Performance of Twin Pontoon Floating Breakwater

The lateral separation ratio ($S/D$) between the twin pontoons of a floating breakwater (TPFB) is one of the prominent factors that attenuate wave energy transmission and reflection. In fact, a numerical investigation of optimum TPFB $S/D$ is inevitably required. To accommodate such a requirement, a numerical optimization model of a genetic algorithm (GA) was developed to assess the optimum $S/D$ primarily through minimizing wave transmission ($K_t$) and reflection coefficients ($K_r$) while maximizing the energy dissipation coefficient ($K_d$). Several parameters, such as wavelengths and $S/D$ ratios including a set of optimization criteria, were taken into account in the simulation, where the optimum solution was then selected from various populations. In addition to the current GA simulation, the optimum $S/D$ was evaluated and quantified by the values of $K_t$, $K_r$, and $K_d$, in which the reduction of some flow parameters was visualized via computational fluid dynamics. The results revealed that the GA simulation is effectively capable of determining global trade-offs between $K_t$, $K_r$, and $K_d$. As compared with the existing model, $K_t$ and $K_r$ decreased to less than 0.3 and 0.4, respectively, whereas $K_d$ increased up to 0.9, resulting in optimum TPFB hydrodynamic performance. Hence, the elaboration of this optimization algorithm can serve as a conceptual design to find an optimum $S/D$ for the twin pontoons of a floating breakwater.