| 1. |
- Kuplis, William, et al.
(författare)
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Investigation of CO2 emissions reduction for a 150 m electric catamaran by CFD analysis of various hull configurations
- 2024
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Ingår i: Journal of Engineering for the Maritime Environment (Part M). - : SAGE Publications. - 1475-0902 .- 2041-3084.
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Tidskriftsartikel (refereegranskat)abstract
- A 150 m electric wave-piercing catamaran concept from Incat Tasmania is analysed using CFD to explore the hydrodynamic impact of operating speed and hull separation on vessel performance and CO2 emissions reduction. Over the investigated speed range of 0.2 < Fr < 0.4, interference factors are evaluated for four demihull separation ratios (s/L) and two demihull slenderness ratios (L/∇1/3). The implications on total life-cycle CO2 emissions are presented as a function of total vessel resistance, and the significance discussed. A separation ratio of s/L = 0.220 provides the lowest overall resistance, however other configurations provide superior results for specific Froude numbers. The concept of transportation capacity is introduced and used to demonstrate the advantage of slower speeds for the electric powertrain through identification of a critical Froude number Fr = 0.35, above which transportation capacity is reduced as a consequence of the low energy density of Nickel Manganese Cobalt (NMC) batteries. A comparison is also made between the electric and equivalent LNG and diesel powertrains to demonstrate the effect of fuel carbon intensities on standardised vessel CO2 emissions. Through analysis of the transportation capacity and emissions reduction of the electric vessel, a speed of Fr = 0.28 is proposed as a compromise between the two, with further power and emissions reductions achievable near this speed by adopting a narrower hull separation ratio of s/L = 0.151.
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| 2. |
- Lau, Chun-Yu, et al.
(författare)
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A novel CFD approach for the prediction of ride control system response on wave-piercing catamaran in calm water
- 2023
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Ingår i: Ocean Engineering. - : Elsevier BV. - 0029-8018 .- 1873-5258. ; 286, s. 115494-115494
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Tidskriftsartikel (refereegranskat)abstract
- 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∼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) Forcing function. By replacing the geometric mesh with a lift force coefficient and forcing function, 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 forcing function. 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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| 3. |
- Lau, Chun-Yu, et al.
(författare)
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High-speed catamaran response with ride control system in regular waves by Forcing Function Method in CFD
- 2024
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Ingår i: Ocean Engineering. - : Elsevier BV. - 0029-8018 .- 1873-5258. ; 297
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Tidskriftsartikel (refereegranskat)abstract
- 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∼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.
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| 4. |
- Lau, Chun Yu, et al.
(författare)
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Ride-Control Systems Geometries on a High-Speed Catamaran Using a CFD Forcing Function Method
- 2023
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Ingår i: HSMV 2023 - Proceedings of the 13th Symposium on High Speed Marine Vehicles. - : IOS Press. ; , s. 243-252
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Konferensbidrag (refereegranskat)abstract
- Controlling vessel motion using hydrofoils to ensure smoother journeys is a widely adopted practice. Incat Tasmania has implemented the Ride-Control System (RCS) on their Wave-Piercing Catamaran (WPC) fleets, consisting of a T-foil and two stern tabs. To efficiently evaluate the effectiveness of different RCS geometries, a novel Computational Fluid Dynamics (CFD) approach, the Forcing Function Method (FFM) was developed and validated. The present paper encompasses two main components: a standalone T-foil analysis and an assessment of the influence of various RCS geometries on a WPC by FFM. In the standalone T-foil study, the lift and drag forces were investigated with respect to the angle of attack and immersed depth. The results indicated that the T-foil lift coefficient diminished logarithmically by decreasing the immersed depth smaller than 1 chord length. The present paper utilises the FFM to examine different RCS geometries on a 2.5 m WPC operating at a speed of 2.89 m/s (Fr~0.6). The effectiveness of motion control is evaluated by measuring the changes in sinkage and trim over time after deflecting the FFM T-foil by ±15∘ in calm water. Through these CFD simulations, the impact of total planform area, number of T-foils, and longitudinal location of the T-foil were analysed. It was found that controllability of motion was a function of total planform area, regardless of the number of foils, and although moving the T-foil away from the bow reduces motion control in trim, it does not affect sinkage significantly. The study also highlights the efficiency and accuracy of the FFM method for integrating hydrofoils into marine vehicle simulations. These insights contribute to the advancement of RCS development and offer valuable guidance for future research and design of hydrofoil systems. The proposed FFM approach has the potential to expedite the development process and enhance the performance of hydrofoil-equipped vessels in diverse operating conditions.
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