• Title/Summary/Keyword: 날개설계

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Technology Trends and Patents Analysis of Auger bit for Deep Cement Mixing (DCM) Method (심층혼합처리 공법용 오거비트의 기술동향 및 특허분석)

  • Min, Kyongnam;Lee, Dongwon;Lee, Jaewon;Kim, Keeseok;Yu, Jihyung;Jung, Chanmuk;Hoang, Truong Xuan;Kwon, Yong Kyu
    • The Journal of Engineering Geology
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    • v.28 no.3
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    • pp.431-441
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    • 2018
  • To set up the future research and development direction for Auger bit, this study analyzed publicized patent trends of Deep Cement Mixing method (DCM) in Korea, USA, Japan, and Europe. DCM method was firstly classified into wing shapes and the number of rods according to the technical scope, and secondly, classified into 8 types according to type of screw and rotation axial. A total of 2,815 patents were searched and 448 validated patents were selected through de-duplication and filtering. As a result of the analysis of the portfolio through the number of patents and growth stages, it was selected as the core technology that auger is deemed to have high growth potential and if there is a patent similar to core technology through a patent barrier analysis, the basic data is suggested to develop the design around and differentiated technologies.

Numerical Investigation of Aerodynamic Characteristics around Micro Aerial Vehicle using Multi-Block Grid (MULTI-BLOCK 격자 기법을 이용한 초소형 비행체 주위 공력 특성 해석)

  • Kim,Yeong-Hun;Kim,U-Rye;Lee,Jeong-Sang;Kim,Jong-Am;No,O-Hyeon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.6
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    • pp.8-16
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    • 2003
  • Aerodynamic characteristics over Micro Aerial Vehicle(MAV) in low Reynolds number regime are numerically studied using 3-D unsteady, incompressible Navier-Stokes flow solver with single partitioning method for multi-block grid. For more efficient computation of unsteady flows, this flow solver is parallel-implemented with MPl(Message Passing Interface) programming method. Firstly, MAV wing with not complex geometry is considered and then, we analyze aerodynamic characteristics over full MAV configuration varying the angle of attack. Present computational results show a better agreement with the experimental data by MACDL(Micro Aerodynamic Control and Design Lab.), Seoul National University. We can also find the conceptually designed MAV by MACDL has the static stability.

Flight Range and Time Analysis for Classification of eVTOL PAV (eVTOL PAV 유형별 항속거리 및 항속시간 분석)

  • Lee, Bong-Sul;Yun, Ju-Yeol;Hwang, Ho-Yon
    • Journal of Advanced Navigation Technology
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    • v.24 no.2
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    • pp.73-84
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    • 2020
  • To overcome ground congestions due to growing number of cars, a lot of companies have proposed personal aerial vehicle (PAV). Among PAV, electric vertical take-off and landing (eVTOL) aircrafts capable of vertical take-off and landing with electric power are drawing attention, and their configurations vary from multicopters to tilt ducted fans. This study tries to analyze the characteristics of each eVTOL design configurations. Parasite drag was calculated using component build up method for Vahana, Aurora, Volocopter representing each eVTOL PAV type of tilt-wing, compound, and multicopter. Wetted area and induced drag was calculated using OpenVSP and XFLR5 that are aircraft design and aerodynamic analysis software. The batteries used in the eVTOL PAV was assumed as Tesla 2170 batteries and flight ranges were calculated. Also, energy consumption and maximum flight time for the given mission profile including take-off and landing, cruising segments were compared for each eVTOL.

An efficient method for fluid/structure interaction analysis considering nonlinear structural behavior (비선형 구조 해석과 공력 해석의 효율적인 연계 알고리즘에 대한 연구)

  • Kim, Euiyoung;Chang, Seongmin;Lee, Dongho;Cho, Maenghyo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.11
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    • pp.957-962
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    • 2012
  • Fluid/structure interaction (FSI) analysis is necessary to predict the response of a system in which aerodynamic pressure causes deformation of the structure, and vice versa. In dealing with a nonlinear behavior of the structure, however, a simple iterative algorithm of aerodynamic analysis with structural analysis yields no accurate results since aerodynamic pressure need to be changed in accordance with the deformation of structures. In this study, we explore an efficient and accurate method for integrating FSI analysis into structural nonlinear systems. During the course of nonlinear structural analysis, loading conditions are periodically updated by aerodynamic analysis. The accuracy and efficiency of the method is demonstrated with a high-aspect-ratio flexible wing of Global Hawk.

Initial Sizing of a Glider Type High Altitude Long Endurance Unmanned Aerial Vehicle Using Alternative Energy (대체에너지를 사용한 글라이더형 고고도 장기체공 무인항공기의 초기사이징)

  • Han, Hye-Sun;Kim, Chan-Eol;Hwang, Ho-Yon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.1
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    • pp.47-58
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    • 2014
  • In this research, the initial sizing of a HALE(High Altitude Long Endurance) UAV which uses solar power and hydrogen fuel cell as an alternative energy was performed. Instead of a wing box type, a glider type was chosen since it is relatively easy to get a data thanks to many researches abroad. Maximum takeoff weight is around 150Kg and the propulsion system is composed of motor, propeller, solar cell, and hydrogen fuel cell which can be recharged through electrolysis. Maximum takeoff weight was estimated as aspect ratio, wing span, wing area change while considering energy balance of required energy which is necessary for flight during the entire day and available energy which can be taken from the solar cell.

Development of Flight Control System for Gliding Guided Artillery Munition - Part II : Guidance and Control (유도형 활공 탄약 비행제어시스템 개발 Part II : 유도 및 제어)

  • Lim, Seunghan;Pak, Changho;Cho, Changyeon;Bang, Hyochoong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.3
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    • pp.229-236
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    • 2014
  • In this paper, the guidance laws and controllers for the gliding guided artillery munition is studied. The gliding guided artillery munition has wings for gliding to increase a range; therefore previous guidance laws and controllers for the guided munition could not be applied. Concepts of vector field guidance and proportional navigation guidance are applied for mid-term and terminal guidance, respectively. The gliding guided artillery munition is operated within wide altitude and speed areas; therefore, the controllers are designed for each area, and gain-scheduling and the linear interpolation technique is applied to compute the appropriate gains.

Control Law Design for a Tilt-rotor Unmanned Aerial Vehicle with a Nacelle Mounted WE (Wing Extension) (체공성능 향상을 위한 확장날개 틸트로터 무인기의 제어법칙설계)

  • Kang, Young-Shin;Park, Bum-Jin;Cho, Am;Yoo, Chang-Sun
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.11
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    • pp.1103-1111
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    • 2014
  • The results of control law design for a tilt-rotor unmanned aerial vehicle that has a nacelle mounted wing extension (WE) are presented in this paper. It consists of a control surface mixer, stability and control augmentation system (SCAS), hold mode for altitude / speed / heading, and a guidance mode for preprogram and point navigation which includes automatic take-off and landing. The conversion corridor and the control moments derivatives between the original tilt-rotor and its variant of the nacelle mounted WE were compared to show the effectiveness of the WE. The nacelle conversion of the original tilt-rotor starts when the airspeed is greater than 30 km/h but its WE variant starts at 0 km/h in order to reduce the drag caused by the high incidence angle of the WE. The stability margins of the inner loop are presented with the optimization approach. The outer loops for the hold mode are designed with trial and error methods with linear and nonlinear simulation. The main control parameter for altitude control of the helicopter mode is thrust command and it is transferred to the pitch attitude command in airplane mode. Otherwise, the control parameter for the speed of the helicopter mode is the pitch attitude command and it is transferred to the thrust command in airplane mode. Therefore the speed and altitude hold mode are coupled to each other and are engaged at the same time when an internal pilot engages any of the altitude or speed hold modes. The nonlinear simulation results of the guidance control for the preprogrammed mode and point navigation are also presented including automatic take-off and landing in order to prove the full control law.

Numerical Investigation of the Effect of Spacing in Coaxial Propeller Multi-Copter in Hovering (멀티콥터용 동축반전 프로펠러 상하 간격에 따른 제자리 비행 공력 특성에 대한 수치적 연구)

  • Sim, Min-Cheol;Lee, Kyung-Tae;Kim, Hae-Dong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.2
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    • pp.89-97
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    • 2020
  • In this study, a numerical analysis was performed on 26 inch single and coaxial propeller using the ANSYS Fluent 19.0 Solver to analyse the effect of the distance between coaxial propellers as one of the design parameter. The Moving Reference Frame (MRF) method was used for single propeller, while the sliding mesh method was used for a coaxial propeller to analyse the flow field varying with azimuth angle. The thrust and power are decreased as the upper and lower propeller approaching each other. As H/D is increased, interference between the propellers is decreased. According to the flow field variable contour of the coaxial propeller, it appears that the change in aerodynamic performance is due to the loading effect and the tip vortex wake effect.

A Study on Conceptual Structural Design for the Composite Wing of A Small Scale WIG Flight Vehicle (소형 WIG선의 복합재 주날개 구조 개념 설계에 관한 연구)

  • Kong, Chang-Duk;Park, Hyun-Bum;Kim, Ju-Il;Kang, Kuk-Jin;Park, Mi-Young
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.11a
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    • pp.179-184
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    • 2005
  • In the present study, conceptual design of the main wing for 20 seats WIG{wing in Ground Effect) flight vehicle, which will be a high speed maritime transportation system for the next generation, was performed. The high stiffness and strength Carbon-Epoxy material was used for the major structure and the skin-spar with a foam sandwich structural type was adopted for improvement of lightness and structural stability. As a design procedure for this study, firstly the design load was estimated with maximum flight load, and then flanges of the front and the rear spar from major bending load and the skin structure and the webs of the spars were preliminarily sized using the netting rules and the rule of mixture. In order to investigate the structural safety and stability, stress analysis was performed by Finite Element Codes such as NASTRAN/PA TRAN[6] and NISA II [7]. From the stress analysis results, it was confirmed that the upper skin structure between the front spar and rear spar was very unstable for the buckling. Therefore in order to solve this problem, a middle spar and the foam sandwich structure at the upper skin and the web were added. After design modification, even thought the designed wing weight was a little bit heavier than the target wing weight, the structural safety and stability of the final design feature was confirmed. Moreover, in order to fix the wing structure at the fuselage, the insert bolt type structure with six high strength bolts was adopted for easy assembly and removal.

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HAT Tidal Current Turbine Design and Performance Test with Variable Loads (조류발전용 수평축 터빈의 형상설계 및 가변 부하를 이용한 성능실험)

  • Jo, Chul-Hee;Rho, Yu-Ho;Lee, Kang-Hee
    • New & Renewable Energy
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    • v.8 no.1
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    • pp.44-51
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    • 2012
  • Due to a high tidal range of up to 10 m on the west coast of Korea, numerous tidal current projects are being planned and constructed. The turbine, which initially converts the tidal energy, is an important component because it affects the efficiency of the entire system. Its performance is determined by design variables such as the number of blades, the shape of foils, and the size of a hub. To design a turbine that can extract the maximum power on the site, the depth and duration of current velocity with respect to direction should be considered. Verifying the performance of a designed turbine is important, and requires a circulating water channel (CWC) facility. A physical model for the performance test of the turbine should be carefully designed and compared to results from computational fluid dynamics (CFD) analysis. In this study, a horizontal axis tidal current turbine is designed based on the blade element theory. The proposed turbine's performance is evaluated using both CFD and a CWC experiment. The sealing system, power train, measuring devices, and generator are arranged in a nacelle, and the complete TCP system is demonstrated in a laboratory scale.