| 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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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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