• Journal of Animal Environmental Science
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• v.20 no.2
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• pp.57-62
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• 2014

It is very important, if necessary, to remotely monitor and control the body conditions and behavior of livestock as well as the environment of stall using ubiquitous ict, in order to improve the health and productivity of livestock. With the aim of developing a stall management system, this study investigated users' needs, analyzed them to design systems, developed a web-system and an app for stall management, then applied them to a test-bed. The use of the app developed will make it easy for livestock farmers to easily monitor and control environment of stall using their smartphones and allow them to take care of stall more efficiently.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.3 s.22
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• pp.116-123
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• 2005

An experimental investigation on the static and dynamic stall characteristics of elliptic airfoil was performed by PIV velocity field measurements. The flow Reynolds number was $3.13{\times}10^5$ and the reduced frequency of the pitch oscillation ranged from 0.075 to 0.125. The onset of static stall was caused by boundary layer separation which started at the trailing edge and progressed toward the leading edge. However, dynamic stall was caused by the vortex shed at the leading edge region and the flow field showed a vortex dominated flow with turbulent separation and alternate vortex shedding. The increase of reduced frequency increased the dynamic stall angle of attack and intensified the flow hysteresis in the down-stroke phase.

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.115-119
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• 2004

The effect of a continuous blowing or suction on an oscillating 2-D NACA0012 airfoil was investigated numerically for the dynamic stall control. The influence of control parameter variation was also studied in the view point of aerodynamic characteristics. The result showed that the blowing control kept a higher lift drag ratio before stall angle but the dynamic stall angle was not exceed to without control result. As the slot position was closer to leading edge, the positive control effect becomes greater. The stronger jet and the smaller jet angel made more favorable roles on the control performance. In the cases of the suction, the overall control features were similar to those of the blowing, but dynamic stall angle was increased, i.e. suction was more effective to control dynamic stall. It was also founded that the suction control was showed better control effect as the slot position moves to trail edge within thirty percentage of chord length. In the simulation for the jet strength and the jet angle control, the same tendencies were observed to those of blowing cases.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.5
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• pp.10-17
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• 2004

To achieve the advanced forward flight performance of helicopter, the passive control methods for enhancement of the dynamic stall characteristics of rotor blades are studied. To enhance the dynamic stall characteristics of the rotor blades, it is essential to improve the lift performance and the pitching moment performance simultaneously with the control of the separation on the rotor blades. For this point of view, both the fixed droop leading edge and the Gurney flap which are simply realized are used for control of the dynamic stall in severe dynamic stall conditions. From this study, the combination of both passive control methods showed dramatic enhancement of lift and pitching moment performance in dynamic stall than previous research results.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.37-39
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• 2010

Aerodynamic analysis was done for a fuselage and wing configuration of a mid-sized aircraft using 3-dimensional Navier-Stokes solver. Various turbulent models including a transitional SST were implemented to observe a dynamic stall as well as cruise characteristics. Also, different mesh moving methods were evaluated. Flow hysteresis which causes dynamic stall was investigated through flow field investigations.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.236-239
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• 2006

500MW급 대용량 보일러 통풍계통의 Fan Stall 감시 장치는 Fan 이상 발생시 Fan을 보호하기 위하여 정지시키는 기능을 한다. 그러나 Fan Stall 감시 장치의 빈번한 고장으로 신뢰성이 저하되고 운전에 영향을 미치므로 이것을 DCS Logic으로 구성하여 신뢰성을 향상시켰다.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2434-2436
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• 2001

500MW급 대용량 보일러 통풍계통의 Fan Stall 감시장치는 Fan 이상 발생시 Fan을 보호하기 위하여 정지시키는 기능을 한다. 그러나 Fan Stall 감시장치의 빈번한 고장으로 신뢰성이 저하되고 운전에 영향을 미치므로 이것을 DCS Logic으로 구성하여 신뢰성을 향상시켰다.

• Proceedings of the KAIS Fall Conference
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• 2006.11a
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• pp.191-194
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• 2006

500MW급 대용량 보일러 통풍계통의 Fan Stall 감시 장치는 Fan 이상 발생시 Fan을 보호하기 위하여 정지시키는 기능을 한다. 그러나 Fan Stall 감시 장치의 빈번한 고장으로 신뢰성이 저하되고 운전에 영향을 미치므로 이것을 DCS Logic으로 구성하여 신뢰성을 향상시켰다.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.16 no.3
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• pp.1-6
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• 2008

The stalling speed flight test of light airplane, ChangGong-91, was performed to acquire the certification. With power-off engine condition, the wings level stall flight tests were conducted at the aircraft configuration of various flap angle - clean, 20degree, and full flap, respectively. They were performed considering with the combination of the maximum and minimum test weight, and forward and afterward center of gravity. The stalling speeds and the minimum speeds of light airplane were determined from the results of flight test. Also, the appropriateness of stall warning speeds are evaluated through the flight test measures. The airplane is recoverable only with pitch control and engine throttle from stall state without exceptional operation.

• The KSFM Journal of Fluid Machinery
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• v.2 no.2 s.3
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• pp.5-12
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• 1999

This study presents the measured unsteady flctuation of impeller discharge flow for a centrifugal compressor in an unstable operating region. The characteristics of the blade-to-blade flow at rotating stall onset were investigated by measuring unsteady velocity fluctuations at several different diffuser axial distances using a hot wire anemometer. The flow characteristics in terms of the radial and tangential velocity components and the flow angle distribution at the impeller exit were analyzed using phase-locked ensemble averaging techniques. As a result, increase or decrease of the radial velocity component during the rotating stall is dominated by that of the suction side. The radial velocity distributions show the opposite trends in the regions where the radial velocity during rotating stall onset increases and decreases.