• 대한기계학회논문집
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• 제18권7호
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• pp.1808-1817
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• 1994

Unsteady aerodynamic analysis of an aircraft is done using a frequency domian 3-D panel method. The method is based on an unsteady linear compressible lifting surface theory. The lifting surface is placed in a flight patch, and angle of attack and camber effects are implemented in upwash. Fuselage effects are not considered. The unsteady solutions of the code are validated by comparing with the solutions of a hybrid doublet lattice-doublet point method and a doublet point method for various wing configurations at subsonic and supersonic flow conditions. The calculated results of dynamic stability derivatives for aircraft are shown without comparision due to lack of available measured data or calculated results.

• 대한기계학회논문집B
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• 제33권12호
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• pp.961-967
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• 2009

A 3-dimensional numerical investigation of a WIG effect vehicle with DUP (direct underside pressurization) is performed to predict aerodynamic characteristics and the static height stability. DUP can considerably reduce take-off speed and minimize the hump drag while the vehicle accelerates on the water to take off. The DUP of the model vehicle, Aircat, consists of a propeller in the middle of the fuselage and an air chamber under the fuselage. The air accelerated by the propeller comes into the camber through the channel in the middle of fuselage and augments lift by changing its dynamic pressure to static pressure dramatically. However, the air accelerated by a propeller produces excessive drag and reduces static height stability.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.719-722
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• 2001

Paraglider has been used for a good air sports instrument by many people in the world though its short history. And manufacturers have improved it continuously. It has the great growth from the first model like parachute to the latest model that has the extreme speed, but we can improve it in more parts. In this paper, we will show the method which can improve its performance by using Axiomatic Approach.

• 산업기술연구
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• 제19권
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• pp.43-50
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• 1999

Vehicle suspensions can be regarded as interconnection of rigid bodies with kinematic joints and compliance elements such as springs, bushings, and stabilizers. Design of a suspension system requires detailed specification of the interconnection point (or so called hard points) and characteristic values of compliance elements. During the design process, these design variables are determined to meet some prescribed performance targets expressed in terms of SDFs (Static Design Factors), such as toe, camber, compliance steer, etc. This paper elaborates on a systematic approach to achieve optimum design of suspension systems.

• Journal of Advanced Marine Engineering and Technology
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• 제28권8호
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• pp.1258-1269
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• 2004

The fluid dynamic characteristics of a circular arc type sea anchor were calculated by a discrete vortex method. The flow for the surface of the sea anchor was represented by arranging bound vortices at adequate intervals. The simulations were performed by assuming that the separations occur at edges. With time, the drag coefficient was almost constant but the lift coefficient oscillated in a cycle due to von Karman's vortex street. As the camber ratios increase, the drag coefficient and Strouhal number were almost constant but the oscillating amplitude of the lift coefficient increased largely.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.607-612
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• 2000

A slitter, also called a roll slitter or rewinding machine, is a sort of machinery to cut sheet materials in rolls continuously in the longitudinal direction. Recently slitter line users have requiring higher wuality and precision in products in addition to high productivity. In this paper, on effect of clearance on shear planes in slitting of S.K.B(shrinkage Bnad) is performed by using finite element method. The results obtained are as follows: (1)Load stroke curves show decreasing maximum force when increasing the clearance. (2)Effective strain decreases when the clearance increases. (3)Deformation is concentrated along the very narrow shear band.

• 한국정밀공학회지
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• 제16권4호통권97호
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• pp.26-36
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• 1999

A general procedure for determining the optimum location of suspension hard points with respect to kinematic design parametes is presented. Suspensions are modeled as connection of rigid bodies by ideal kinematic joints. Constraint equations of the kinematic joints are expressed in terms of the generalized coordinates and hard points. By directly differentiating the constraint equations with respect to the hard points, kinematic sencitivity equations are obtained. In order to cope with algebraic complexity associated with the differentiation process, a symbolic computation technique is used. A performance index is defined in terms of static design parameters such as camber, caster, toe, ect.. Gradient of the performance index can be analytically computed from the kinematic sensitivity equations. Optimization results show the effectiveness and validity of the procedure, which is applicable to any type of suspension if its kinematic configurations are given.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.594-601
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• 1997

Propeller fans are commonly equipped in outdoor units of air-conditioners to provide effective cooling in a dried heat exchanger. A new design technique was developed to satisfy requirements of aerodynamic and aeroacoustic performance, which employs the intersection method of two cylinders for mean camber line. Three proto-types of propeller fan including Palm-Shaped, Highly-Swept(PSHS) fan (proto 3)were not only to provide low lift forces for dipole sound, but also to reduce the organized tip vortices interacting with the fan guide causing narrow-banded rotating instabilities. Cross-correlation technique was applied to study flow noise source characteristics for three proto-type fans designed. The cross-correlations between a microphone at far field and a hot-wire sensor at near field show that flows near hub region of proto 3 fan are less organized and the flow structures especially at high flow rate coefficients for proto 3 fan are less correlated with noise generated than other proto-types fans.

• 한국자동차공학회논문집
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• 제7권5호
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• pp.186-193
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• 1999

In this paper, a full vehicle model is developed to analyze toe and camber changes due to rack height variation and compliance. The AutoDyn7 program developed in G7 project is used for the computer simulation. Steady state cornering test was done to find the understeer gradient. Imposing a pulse steer input, Frequency Response Function(FRF) of yaw rate and lateral accelerations were evaluated. To verify the stability, the rhombus using four parameters is employed. Steer characteristics were evaluated by changing the rack height and the bushing lateral stiffiness. which installed between the low control arm and the chassis.

• EDISON SW 활용 경진대회 논문집
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• 제3회(2014년)
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• pp.654-658
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• 2014

풍력발전은 재생에너지로써 유망한 대체 에너지원으로 각광받고 있으며, 국내에서는 이미 영덕, 영양 등의 풍력단지가 가동 중에 있다. 그러나 장기간 사용되어온 터빈이 반 이상이며, 그 중에서도 바람의 영향을 많이 받는 블레이드는 끝단 Tip이 벌어지는 파손이 발생하곤 한다. Blade Field의 유지보수를 통해 수명연장이 가능하나, 형상변화로 공력특성에 영향을 미치게 된다. 본 연구에서는 MEXICO 터빈용 블레이드의 Tip부분에 대해서 EDISON을 활용하여, 수리로 인해 변경된 Blade의 공력특성 변화를 분석하였다. 형상변경은 상용 프로그램 Pontwise로 작업했으며, 익형 주위의 유동을 2D비압축성 유동으로 가정하고 EDISON CFD의 2D_Incomp-2.1_P solver를 수치해석을 수행하였다.