Physics-informed neural networks in support of modal wavenumber estimation

Abstract A physics-informed neural network (PINN) enables the estimation of horizontal modal wavenumbers using ocean pressure data measured at multiple ranges. Mode representations for the ocean acoustic pressure field are derived from the Hankel transform relationship between the depth-dependent Green's function in the horizontal wavenumber domain and the field in the range domain. We obtain […]

Direct hydroacoustics analyses of pipe orifice using lattice Boltzmann method

Abstract Acoustic waves in water pipes pose a structural threat but also offer a valuable tool for non-invasive inspection. Complex pipe geometries such as bends and surface liners create complex fluid boundaries, triggering interactions between fluid flow and acoustics. The lattice Boltzmann method (LBM) excels at capturing these interactions near complex boundaries, in contrast to […]

Changes in holding time depending liquid filling ratio, heat transfer parameters, and shape of the tank

Abstract This study simulates the self-pressurization of liquefied hydrogen using a three-element lumped model. We analyze the effects of liquid filling ratio, heat flux distribution, interface heat transfer parameters, and tank shape on pressure build-up, which can vary due to ship transportation conditions. Key findings are: lower liquid levels correlate with faster pressure build-up; the […]

Greenhouse gas emissions of shipping with onboard carbon capture under the FuelEU Maritime regulation: A well-to-wake evaluation of different propulsion scenarios

Abstract International shipping has extended its decarbonization strategy to reduce greenhouse gas emissions beyond onboard CO2 emissions. Onboard carbon capture and storage systems are being investigated as a potential solution for fossil-fueled ships, however there is a lack of knowledge on the reduction of well-to-wake greenhouse gas emissions that could be enabled. Considering the ambitious emission […]

Data-driven framework with theoretical modelling to evaluate fuel savings through air lubrication system

Abstract This study introduces a data-driven and theoretical framework to evaluate the Air Lubrication System (ALS) in maritime operations, analyzing its impact on fuel consumption under varied conditions. The operational data from three 325k series ships is used to examine ALS performance over operational scenarios, including different drafts and speeds. The Partial Cavity Drag Reduction […]

Data-driven modeling and regression analysis on ship resistance of in-service performance

Abstract This study employs operational data to model ship resistance, aiming to bridge the gap between controlled experiments and real-world conditions. It comprehensively analyzes wind, waves, and currents, employing nonlinear regression and z-score filtering. The model is validated using data from three identically designed ships operating on the similar servicevoyages. Key findings reveal significant impacts […]

Experimental datasets of surface piercing propellers operating in open-water conditions

Abstract The present experimental datasets provide the open-water performance characteristics of surface-piercing propellers under various operating conditions. The open-water tests were conducted in a towing tank, considering various pitch ratios, immersion ratios, shaft inclination angles, and Froude numbers. The model propellers were of two different modified shapes of the Model-841-B with different pitch ratios. Thrust, […]

Water Entry of a Sphere Moving along a Circular Path at a Constant Speed

Abstract When a marine propeller rotates in partially submerged conditions, air is entrained from above the undisturbed free-surface, which is called the reference surface, and the ventilated air surrounds the propeller blades, causing thrust loss and excessive vibration, all of which seriously damage the durability of the propeller shaft system of a ship. In the […]