Optimisation using smoothed particle hydrodynamics with volume-based geometry control

This work explores how smoothed particle hydrodynamics (SPH) may be applied for fluids optimisation problems. To achieve this, a newly developed volume of solid geometric parameterisation is applied that implicitly allows large geometric changes as well as topological changes. The meshless nature of SPH has long been an advantage, but when combined with the parameterisation presented here, optimisation calculations are able to make unlimited changes in the geometry without user intervention. To demonstrate the benefits this pairing of techniques affords for free-surface problems, three model optimisations and objective functions are considered: improvement of discharge coefficient through a nozzle, maximisation of damping in a pivoting tank and minimisation of wave overtopping for a simplified coastal defence. For the wave problem, varying constraints are explored and a time-recorded particle boundary condition is applied to accelerate the optimisation process. In each of the cases the optimisation finds a significant improvement in the objective function and shows how constraint selection influences the performance of the final design.