An innovative Computational Fluid Dynamics (CFD) approach, defined as the forcing function method (FFM), is used to simulate Ride Control Systems (RCS) on an Incat Tasmania Wave-Piercing Catamaran vessel in analysis c...
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An innovative Computational Fluid Dynamics (CFD) approach, defined as the forcing function method (FFM), is used to simulate Ride Control Systems (RCS) on an Incat Tasmania Wave-Piercing Catamaran vessel in analysis conducted at model scale. This study examines the FFM's capabilities in head sea regular waves using CFD, and considers three ride control scenarios: Bare Hull (BH), Pitch Control (PC), and Non-Linear Pitch Control (NL PC). CFD-predicted vessel motion is compared to experimental data from a 2.5 m Incat Tasmania Wave-Piercing Catamaran model at 2.89 m/s (Fr similar to 0.6), showing good agreement. Modification in FFM to account for emergence of control surfaces from the water, and time series of lift forces produced by FFM are also discussed. The frequency domain analysis using heave and pitch Response Amplitude Operators (RAOs) showed a good of agreement in motion reduction trends between CFD and experiments, providing a high level of confidence in the FFM predictions. Dimensionless vertical accelerations are calculated along the length of hull using the various control algorithms, showing a considerable reduction in acceleration, especially at the bow. These outcomes demonstrate the novel CFD approach, FFM, that can be used by ship designers for predicting high-speed vessel motion reductions from deployment of RCS, and thereby improving passenger comfort.
Ride Control Systems (RCS) on high-speed vessels help improve passenger comfort and mitigate dynamic structural loads. Incat Tasmania Wave-Piercing Catamarans (WPC) use RCS consisting of a central T-foil, and a stern ...
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Ride Control Systems (RCS) on high-speed vessels help improve passenger comfort and mitigate dynamic structural loads. Incat Tasmania Wave-Piercing Catamarans (WPC) use RCS consisting of a central T-foil, and a stern tab on each deli-hull. Previous towing tank studies on a 2.5 m model of a 112 m WPC have demonstrated significant reductions in motions with the use of a T-foil and stern tabs. To extend this work, this study examines the use of Computational Fluid Dynamics (CFD) to predict the ship's response with RCS implemented. The model-scale WPC was simulated in calm water conditions, traveling at 2.89 m/s (Fr similar to 0.6), with step responses applied at the T-foil and stern tabs, to determine the trim and sinkage. The T-foil was implemented in CFD using two methods: 1) Overset mesh;2) forcingfunction. By replacing the geometric mesh with a lift force coefficient and forcingfunction, the setup difficulty and computational cost were reduced. Only about 7% difference was observed between CFD and experiments, but no significant difference was found between the methods of overset mesh and forcingfunction. This has proven the ability of CFD to predict vessel responses to RCS step changes in calm water, and the simplified forcing function method is recommended.
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