Alan C McClure Associates (ACMA) performed a seakeeping analysis on a Tandem Catamaran using computational fluid dynamics (CFD). The challenge was how to perform a seakeeping analysis in a commercially viable fashion. ACMA utilized an unsteady RANS method to model regular waves of various wave encounter periods interacting with the vessel. ACMA then post processed results to create response amplitude operators (RAO) from the simulations.
This paper reviews the strategy for optimization of the mesh refinements within the wave zone, the timestep, and simulation run time. The results of this optimization yielded a careful balance between computational cost and accuracy. The CFD analysis was supported by validation and error analysis, which the paper summarizes. Results also include a computational budget for seakeeping analysis, visualizations of volume fraction dispersion, and plots of response amplitude operators. All results include thorough discussion on successes and challenges with maintaining simulation quality within the project budget.
This work revealed the current economic limitations of CFD. At this point, CFD is not yet ready for unrestricted application to seakeeping. Limited scope applications are possible, but generalized seakeeping applications require extensive project budgets.