• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.9
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• pp.759-768
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• 2016

Design and performance analysis of propeller for solar-powered HALE UAV, EAV-3 are conducted. Experiment points of design variables are obtained by using Design of Experiment(DOE) and Kriging meta-model is generated for objective and constraints function. The geometry of propeller is designed by evaluating the response surface with requirement and restrictions. The validity of the design is verified by meta-model based optimization. Computational analyses are carried out by using commercial CFD code and the results are compared with those from a design code and wind tunnel test. The results showed good agreement with predictions of the design code at the design altitude. Also, it is confirmed that the blockage effect due to the measurement device and support strut is included in the test data and the results including this effect compare well with the test data.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.4
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• pp.1491-1500
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• 1996

Unstable performance deterioration was found on the performance curve of a small propeller fan with a back plate. To investigate this phenomenon and the effects of the back-plate on the performance of the fan, performance tests and flow measurement using 3-hole pitot tube were carried out. Measurements showed that when the flow rate is small, the radial flow dominates, and when the flow rate is large, the axial flow dominates. Performance characteristic of the propeller fan changes from radial to axial type as the flow rate increases. Unstable performance changes are the result of type change of the flow through the fan.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.209-220
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• 2013

The process of designing and building a human-powered aircraft (HPA) and its performance analysis are introduced in this paper. Light Bros, the Chungnam National University HPA team, has developed Volante, a HPA, to compete in the 2012 exhibition of human-powered aircraft hosted by Korea Aerospace Research Institute. The power train system is composed of a two-blade propeller and Bevel-type gear and the ground test bed is built to simulate the operation. A study has been made to find a efficient propeller based upon the test result of thrust and power available from a pilot under various propeller conditions and running time. The load and structural analysis is conducted for the glider-shaped wing made of composite material which has very high aspect ratio. The spar is analyzed using finite element modeling followed by the comparison of its displacement and strain on structural test. As a result, the performance and safety is confirmed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.16-20
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• 2003

Recently, The fast change of fishing boat fishery surrounding environment is connected by request of fan shape development that meet in restructuring of existing fishing boat fishery and new community, economical surrounding. In southern sea district along the coast work and district along the coast fishing bats that sail to exposed propeller fishing net, rope etc.. cold real condition that accident is increasing every year. This study is thing which analyze main performance of minuteness water jet type district along the coast fishing boat through model examination to propeller protection tunnel sticking district along the coast fishing boat that correct existing stem shape for marine accident prevention of district along the coast fishing boat in viewpoint such as ideal and examines.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.2
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• pp.125-131
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• 2017

In order to develop test and performance analysis techniques for a CRP propulsion, a CRP dynamometer which can be installed inside the model ship was designed and manufactured. The object ship was the 16000TEU container carrier, which has test results for the single propeller. The design concept of the present CRP is that forward & after propellers have the same power ratio and their RPM ratio is 0.75:1. To begin with, we checked the performance of the CRP dynamometer through the calibration and then installed it inside the model ship. After the model ship setup including the design CRP and the rudder in the Large Cavitation Tunnel(LCT), a series of model tests composed of power ratio check, propeller behind wake(PBW) test, cavitation observation and pressure fluctuation tests was conducted. Through the model test and data analysis for CRP, the experimental technique was established and the improved method for CRP design was suggested.

• The KSFM Journal of Fluid Machinery
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• v.17 no.3
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• pp.25-32
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• 2014

The main objective of this study is to validate the performance characteristics of newly developed micro propeller turbine based on experimental model test. For this purpose, Measurements of efficiency and cavitation tests with variations on the guide vane opening, blade rotational speed, head and load are carried out according to the IEC standard for model testing. From the tests and scale up calculation, the maximum prototype and model efficiency of the runner blade reaches as high as 90.87 % and 90.27 % respectively. Test results show that good cavitation behavior is covered in the range of output 50kW and 100 kW.

• Journal of Aerospace System Engineering
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• v.18 no.3
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• pp.76-85
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• 2024

Recently, from a global perspective, the use of small unmanned aerial vehicles in terrorism and warfare is increasing, and the need for anti-drone shooting training targeting small UAVs is increasing. However, in reality, there are many cases in Korea where anti-drone shooting training is restricted, due to complaints such as noise. In this paper, we describe the development and testing of an electric-powered direct strike type high-speed, low-noise small aerial target drone. To achieve the flight speed and endurance required for shooting training, target drone sizing was performed, and aerodynamic performance analysis was conducted using a CFD program. Based on the performance analysis, the motor propulsion system was selected and a variable pitch propeller system was designed, and performance tests were performed on a ground test rig. Finally, the target flight speed, flight time, and flight noise level were confirmed through flight tests.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.3
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• pp.90-101
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• 1992

Some practical methods have already been proposed for predicting the characteristics of ship manoeuvring motions at relatively high advance speed. However, these methods can hardly be applied to motions of ships in starting, stoppint, backing and slow steaming conditions, even though such extensive motions are of vital importance from a safety point of view particularly in harbour areas. The method presented here aims at predicting the characteristics of ship manoeuvring at low advance speed, which covers starting, stopping, backing and slow steaming conditions. The force mathematical models at large angles of incidence to the hull as well as under the tilde range of propeller operations are formulated. Simulations of various manoeuvres at low advance speed are carried out for two types of merchant ship, i.e. a LNGC and a VLCC. Comparisons between simulations and corresponding full-scale measurements or free-running model tests provide a first verification of the proposed mathematical models.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.1
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• pp.1-13
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• 1994

Procedures for the development of a preswirl stator-propulsion system for a VLCC 300K are described in this paper. The preswirl stator-propulsion system is one of the compound propulsor systems, which is used for the purpose of recovering propeller slipstream rotational energy by locating a stator in front of the propeller. The preswirl stator-propulsion system can be considered as a most reliable energy saving device because of its simple mechanism. Five stators are designed for the existing hull form and propeller, and their effects are verified by model tests. Open-water test result of the preswirl stator-propulsion system at the cavitation tunnel show $4{\sim}6%$ increase of open-water efficiency compared to that of a propeller without stators. Maximum 6.5% decrease of delivered power at the design speed(15.5knots) is expected with the designed stator based on the analysis results of resistance and self-propulsion test at the towing tank.

• Journal of Aerospace System Engineering
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• v.11 no.6
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• pp.10-16
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• 2017

In order to improve the safety of the multi-copter, Korea Aerospace Research Institute (KARI) performed a wind-tunnel test using an octocopter with the maximum takeoff weight (MTOW) of 28 kg. The wind-tunnel test was performed with three different RPM ranges, 3,500, 4,500 and 5,500 rpm, and three different wind speeds, 3.5, 5 and 7 m/sec. The tested range of the angle of attacks was $-40^{\circ}$ to $20^{\circ}degree$ and ${\pm}90^{\circ}degree$. Vortex ring state (VRS) of the tested multi-copter was located around the vertical descending speed of 6 m/sec and the decrement of thrust was about 13 % at the time of testing. Compared with the single propeller wind-tunnel test result, the propeller efficiency of the octocopter dropped to 10 to 15% depending on the propeller RPM. It is hypothesized that the obtained aerodynamic characteristics by the wind-tunnel test will be used to improve the performance and wind resistance of the multi-copter.