• Title/Summary/Keyword: 깃요소법

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The Flight Trajectory of a Boomerang Simulated with Helicopter Theories (회전익 이론을 이용한 부메랑의 비행 궤적 연구)

  • Jang,Se-Myeong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.1
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    • pp.49-57
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    • 2003
  • The flight trajectory of a boomerang is predicted with the momentum theory (actuating disk theory) and the blade element method generally used as tools to analyze in the rotary-wing aerodynamics. Boomerangs made by students are actually compared with the computational results, utilized to get the physical intuition. The transition from helicopter mode to autogyro mode with the gyroscopic precession is observed in numerical analysis and experiment like a 'flying rotor' after the boomerang taking off. The whole system is shown to be highly nonlinear and very sensitive to the initial conditions. Various flight loci may be obtained if we change the parameters.

Aerodynamic Design of 10 kW-level HAWT Rotor Blades (10 kW급 수평축 풍력 터빈 로터 블레이드의 공력 설계)

  • Chang, Se-Myong;Lee, Jang-Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.10
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    • pp.884-890
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    • 2007
  • The procedure for the aerodynamic design of the rotor blades for 10 kW-level HAWT (horizontal axis wind turbine) has been investigated to be practiced systematically. The approximately optimal shape was designed using an inverse method based on the momentum theory and the blade element method. The configuration was tested in the wind tunnel of the Korea Air Force Academy, and the data was compared with those obtained from the real system manufactured from the present design. From this research, the authors established the systematic technolo for wind turbine blades, and set up the technical procedure which can be extended for the future design of middle and large sized wind turbines.

THE INVESTIGATION OF HELICOPTER ROTOR AERODYNAMIC ANALYSIS METHODS (헬리콥터 로터 공력해석을 위한 수치적 방법 연구)

  • Park, N.E.;Woo, C.H.;Rho, H.W.;Kim, C.H.;Yee, S.J.
    • 한국전산유체공학회:학술대회논문집
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    • 2007.04a
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    • pp.120-124
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    • 2007
  • Helicopters and rotary-wing vehicles encounter a wide variety of complex aerodynamic phenomena and these phenomena present substantial challenges for computational fluid dynamics(CFD) models. This investigation presents the rotor aerodynamic analysis items for the helicopter development and variety aerodynamic analysis methods to provide the better solution to researchers and helicopter developers between aerodynamic problems and numerical aerodynamic analysis methods. The numerical methods to make an analysis of helicopter rotor are as below - CFD Modelling : actuator disk model, BET model, fully rotor model,... - Grid : sliding mesh, chimera mesh / structure mesh, unstructure mesh,... - etc. : panel method periodic boundary, quasi-steady simulation, incompressible,... The choice of CFD methodology and the numerical resolution for the overall problem have been driven mostly by available computer speed and memory at any point in time. The combination of the knowledge of aerodynamic analysis items, available computing power and choice of CFD methods now allows the solution of a number of important rotorcraft aerodynamics design problems.

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Analysis of Relative Contributions of Tonal Noise Sources in Volute Tongue Region of a Centrifugal Fan (원심팬 볼루트 영역내 순음 소음원의 상대적 기여도 분석)

  • Heo, Seung;Kim, Daehwan;Cheong, Cheolung
    • The Journal of the Acoustical Society of Korea
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    • v.33 no.1
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    • pp.40-47
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    • 2014
  • Interaction between the unsteady flow emitted from the blade of the centrifugal fan and the volute tongue region of fan duct is known as the main noise source of the centrifugal fan. In this paper, the relative contributions of the volute tongue region of the centrifugal fan is analyzed to utilize as the foundation data of low noise design. The internal hybrid CAA (Computational Aero-Acoustics) method is used to predict noise radiated from the main noise source. This method is the noise prediction technique using CFD (Computational Fluid Dynamics), Acoustic analogy, and BEM(Boundary Element Method). The relative contributions of the centrifugal fan volute tongue region using the hybrid CAA method show that the region between the cut-off and the scroll has high contribution than the region between the cut-off and the outlet and the hub region of blade has high contribution than the shroud region of blade. These results is utilized as the important data for the development of low noise centrifugal fan.

A Study on the Development of Low-Altitude and Long-Endurance Solar-Powered UAV from Korea Aerospace University (2) - Flight Control and Guidance of Solar Powered UAV - (한국항공대학교 저고도 장기체공 태양광 무인기 개발에 관한 연구 (2) - 태양광 무인기 비행제어 및 유도항법 -)

  • Kim, Taerim;Kim, Doyoung;Jeong, Jaebaek;Moon, Seokmin;Kim, Yongrae;Bae, Jae-Sung;Park, Sanghyuk
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.7
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    • pp.479-487
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    • 2022
  • This paper presents the control and guidance algorithm of a KAU-SPUAV(Korea Aerospace University - Solar Powered Unmanned Aerial Vehicle) which is designed and developed in Korea Aerospace University. Aerodynamic coefficients are calculated using the vortex-lattice method and applied to the aircraft's six degrees of freedom equation. In addition, the thrust and torque coefficients of the propeller are calculated using the blade element theory. An altitude controller using thrust was used for longitudinal control of KAU-SPUAV to glide efficiently when it comes across the upwind. Also describes wind estimation technic for considering wind effect during flight. Finally, introduce some guidance laws for endurance, mission and coping with strong headwinds and autonomous landing.