A study of multi-acoustic black holes considering suitability of attachment positions for suppressing low-frequency vibrations on large motor
Abstract Vibrations generated from machinery in various industries, such as the automotive, aerospace, and shipbuilding industries, must be suppressed for developing low-vibration and low-noise systems. High-frequency vibrations can be easily controlled via damping treatments; however, controlling vibrations in the low-frequency range generated from large machinery is a major challenge. In general, a substantial amount of […]
Deep-reinforcement-learning-based hull form optimization method for stealth submarine design
Abstract The stealth performance of submarines is closely related to their hull forms. In this study, an optimization method based on Deep Reinforcement Learning (DRL) was developed to design submarine hull forms, aimed at maximizing the stealth performance. The DRL optimization technique relied on the decision-making process of an agent for determining actions resulting in […]
Numerical study on the distance between the propeller with pre-swirl duct and rudder considering fatigue characteristics
Abstract Recently, there has been increasing awareness about greenhouse gases, resulting in considerable efforts to increase the fuel efficiency of ships and reduce the amount of gases they emit. Thus, pre-swirl ducts (PSDs) have been widely adopted in ships due to their high fuel efficiency. However, attaching PSDs induces a change in the fatigue characteristics […]
Advanced process design of subcooling re-liquefaction system considering storage pressure for a liquefied CO2 carrier
Abstract Because carbon capture and storage methods are considered greenhouse gas reduction technologies, demand for a large liquefied CO2 (LCO2) carrier to transport captured CO2 to storage sites has arisen. To prevent the emission of boil-off CO2 gas during transport, a CO2 re-liquefaction system would be required. This study suggests a new type of LCO2 subcooling re-liquefaction system for an […]
Experiment and simulation of LNG self-pressurization considering temperature distribution under varying liquid level
Abstract For LNG-fueled ships, estimating the rate of self-pressurization is critical because the pressure limit of an LNG storage tank and the specifications of the boil-off gas processing system depend on the pressure rise rate. However, estimation using a non-equilibrium model exhibits deviated prediction on the pressure increase when thermal stratification is occurred in LNG. […]
Optimal capacity design of amine-based onboard CO2 capture systems under variable marine engine loads
Abstract The International Maritime Organization has adopted a strategy aiming for net-zero greenhouse gas emissions from international shipping, prompting various mitigation technologies to comply with this strengthened strategy. Carbon capture technologies are increasingly being considered to satisfy the IMO strategy. In particular, amine-based carbon capture technologies, which are emerging as the most mature option, have […]
Validation of 4DOF maneuvering coefficients optimization using hydrodynamic force and moment estimated from free-running model test results
Abstract The present study concerns validation of data-driven modeling for ship dynamics from free-running model test results, in terms of estimation of hydrodynamic force and moment, maneuvering coefficients, and maneuver simulation results. An estimation method for the hydrodynamic force and moment from the acceleration of a surface combatant model ship is suggested and compared with […]
Experimentacl investigation of boundary layer transition by wall-mounted elements
Abstract In model tests with low Reynolds numbers (Re), wall-mounted elements are used for promoting boundary layer transition, which aims to imitate the turbulent flow around the full-scale subjects with high Reynolds numbers. Ship model test results are obtained for model-scale ship flow for Re of 105 to 106, and these results are extrapolated to full-scale ship flow […]
Application of amine infused hydrogels (AIHs) for selective capture of CO2 from H2/CO2 and N2/CO2 gas mixture
Abstract This study presents an efficient amine infused hydrogels-based CO2 separation technology from H2/CO2 and N2/CO2 gas mixtures. The amine-infused hydrogels (AIHs) prepared by mixing aqueous amine solution with dried hydrogel particles were exposed to the gas mixtures in static condition, then the absorption capacity of AIHs along with the initial uptake rate were obtained from the experimental […]
Analysis of turning ability of large tankers with and without bulbous bow in calm sea and waves
Abstract The present study introduces an experimental and numerical investigation of the turning ability of two ships with and without a bulbous bow: original and modified KVLCC2 hulls Experiments are performed via free-running model tests in a square basin, and a system-based simulation are performed. The maneuvering coefficients for the system-based solver are obtained via […]
