• Proceedings of the KSRS Conference
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• v.1
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• pp.130-133
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• 2006

Three scatterometers will be launched by Europe, India, and China in the next few years and they will fly in tandem with QuikSCAT of the United States. The potential improvement in coverage will open up new operational and research applications.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.648-656
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• 2022

As environmental regulations such as the International Maritime Organization (IMO)'s strategy to reduce greenhouse gases(GHG) are strengthened, technology development such as eco-friendly ships and alternative fuels is expanding. As part of this, ship propulsion technology using energy reduction and wind propulsion technology is emerging, especially in shipping companies and shipbuilders. By securing wind propulsion technology and introducing empirical research into shipbuilding and shipping, a high value-added market using eco-friendly technology can be created. Moreover, by reducing the fuel consumption rate of operating ships, GHG can be reduced by 6-8%. Rotor Sail (RS) technology is to generate a hydrodynamic lift in the vertical direction of the cylinder when the circular cylinder rotates at a constant speed and passes through the fluid. This is called the Magnus effect, and this study attempted to propose a plan to increase propulsion efficiency through a numerical analysis study on turbulence flow characteristics around RS, a wind power assistance propulsion system installed on a ship. Therefore, C_L and C_D values according to SR and AR changes were derived as parameters that affect the aerodynamic force of the RS, and the flow characteristics around the rotor sail were compared according to EP application.

• Proceedings of the KSRS Conference
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• v.1
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• pp.142-145
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• 2006

The synergism of active and passive microwave techniques for hurricane ocean wind remote sensing is explored. We performed the analysis of Windsat data for Atlantic hurricanes in 2003-2005. The polarimetric third Stokes parameter observations from the Windsat 10, 18 and 37 GHz channels were collocated with the ocean surface winds from the Holland wind model, the NOAA HWind wind vectors and the Global Data Assimilation System (GDAS) operated by the National Center for Environmental Prediction (NCEP). The collocated data were binned as a function of wind speed and wind direction, and were expanded by sinusoidal series of the relative azimuth angles between wind and observation directions. The coefficients of the sinusoidal series, corrected for atmospheric attenuation, have been used to develop an empirical geophysical model function (GMF). The Windsat GMF for extreme high wind compares very well with the aircraft radiometer and radar measurements.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.507-513
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• 2009

The cooling technology of power conversion semiconductors in the propulsion system for the HEMU(High Electrical Multi Unit) are applied in water cooling method and phase change method such as the immersed type and the heat pipe type. Both of cooling systems need a condenser and a fan through forced wind to emit that is radiated heat from electric power conversion semiconductor(IGBT) stack effectively, now in the case of Japanese Fastec 360S, is using ram-air that is flowed in establishing cooling passage to propulsion system for cooling of condenser. In this research, it is that achieved the computing numerical analysis using ADINA of commertial program to examine flow characteristics and pressure distribution of ram-air for a condenser in cooling passage.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.3
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• pp.185-199
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• 2024

Global warming impacts every corner of human life. Maritime transportation and shipbuilding industries are no exception. Recent counteraction in maritime industries is accelerating to meet the zero emission by 2050. Various alternative energy sources have been studied, and recent developments in Europe show that the windship, as a proven technology, can be an attractive candidate to solve the problem. In this paper, as the alternative transportation option, to infer the performances of modern windships, the non-dimensional ratios of past tall ships and windships are studied and reviewed. In addition, the ratios are compared to estimate the position of current and future windships under consideration. It is found that regarding the ratio distributions, the current windships being planned can be either wind-assisted propulsion ships or less fully functional windships than the past tall ships.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.634-643
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• 2004

In this paper are presented a concept of a new supersonic air inlet, which is designated a Multi-Row Disk (MRD) inlet, aiming at performance improvement under off-design conditions, and results of wind tunnel tests examined performance characteristics of the MRD inlet. The MRD inlet is frequently called ‘a skeleton inlet’ because of its appearance. The performance of a conventional axisymmetric inlet with a solid center body (spike) deteriorates under off-design Mach number conditions. It is due to the fact that total pressure recovery (TPR) governed by the throat area of inlet and mass capture ratio (MCR) governed by an incidence position of an oblique shock from the spike tip into the cowl can not be controlled independently in such air inlet. The MRD inlet has the spike that is composed of a tip cone and several disks arranged downstream of it, based on the experimental fact that several deep cavities on a conical surface have little negative effect on the boundary layer growth. The overall spike length of the MRD inlet is adjustable to the given flight speed by changing space between disks so that a spillage flow can be controlled independently from controlling the throat area. It could be made clear from the result of wind tunnel tests that the MRD inlet improves TPR by 10% compared with a conventional inlet with a solid spike under off-design conditions.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1354-1359
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• 2014

A survey is carried out for the future energy sources to be used for ship's propulsion and ship's machinery and operations. 44 global experts from Korea, America, Norway, Denmark, Japan and German who are currently working in the shipyard and offshore fields participated at the survey. Quantitative predications on the market shares of various energy sources, such as oil, LNG, fuel cell, wind energy, solar energy and nuclear energy are made. MPI (market prediction index) is considered as a quantitative index for easy comparison between future's energy sources used for ship's propulsion and operations. It is expected that the MPI of LNG becomes twofold in 2020 against 'before 2016'. It could be also said that hydrogen based fuel cell is expected to increase rapidly for the coming years unless a new alternative energy appears.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.4
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• pp.343-352
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• 2018

In this study, a motion control problem for the vessels towed by tugboats or towing ships on the sea is considered. The towed vessel looks like the barge ship, which is used for many purposes. In these vessels, basically, the power propulsion system is not installed but just towed by a towing vessel such as tugboats with ropes and wires. It means that the motions of towed vessel are basically dependent on the tracking route of towing boat. Therefore, in some cases, undesirable and unpredictable motions may be made by environmental factors such as wave, wind attack and so on. As a result, a collision accident with others may occur during maneuvering situation. Based on these facts, the authors try to encourage the steering performance of the towed vessel by using controllable rudders without any propulsion system. In this study, especially, a controllable vessel with three rudders is considered, and a mathematical model is induced for the future study. The model is described as surge, sway motion and inertia moment by following the general representation method for the surface ship.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.3
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• pp.1-9
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• 1998

The exhaustion of fossil fuels and serious environmental pollution put the concern about non-po llution energy into the world. On the developments of technology, wind energy has been spotlighted as a non-pollution energy in many countries. This study has carried out the aerodynamic and structural design procedure of the lightweight composite rotor blades with an appropriate aerodynamic performance and structural strength for the 500㎾ medium class wind turbine system. The previous design, which is shell-spar structure, is redesigned to shell-spar- sandwich structure for light weight. Large deformation problem from light weight is examined by non-linear analysis. Local buckling occurred under lower stress than failure stress. The buckling analysis is accomplished to confirm the safety of the composite blade. The stress analysis around pin hole joint part at hub is carried out and it is confirmed that the pin hole is not failed. The results show that the resonance of redesigned blade does not happen in operation range.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.713-721
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• 2004

Variable air intake and variable exhaust nozzle of hypersonic engines are designed and tested in this study. Dimensions for variable geometry air intake, ram combustor and variable geometry exhaust nozzle are defined based on the requirements of a pre-cooled turbojet engine. Hypersonic Ramjet Engine is designed as a scaled test bed for each component. Actuation forces of moving parts for variable intake and variable nozzle are reduced by balancing the other force in the opposite direction. A demonstrator engine which includes variable intake and variable nozzle is designed and the components are fabricated. Composite material with silicone carbide is applied for high temperature parts under oxidation environment such as leading edge of the variable intake and combustor liner. Internal cooling structure is adopted for both moving and static parts of the variable nozzle. Pressure recovery and mass capture ratio of the variable intake at Mach 5 is obtained by a hypersonic wind tunnel test. Flow characteristics of the variable nozzle are obtained by a low temperature flow test. Wall temperature and heat flux of the nozzle at Mach 3 is obtained by a firing test. As results, the intake and the nozzle are proved to be used at designed pressure and temperature environment.