• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.594-599
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• 2015

활주로에서 발생하는 측풍이나 돌풍 등은 항공기의 이 착륙 안정성에 큰 영향을 미친다. 일반적으로 활주로를 건설 할 때 측풍에 대하여 많은 고려를 하지만, 이는 단순히 건설지형 주변에서 발생되는 기상 현상에 대한 데이터를 사용할 뿐 활주로가 완성된 이후에는 활주로 주변 지형 및 환경이 변하게 되어 활주로 건설 초기에 측정된 풍향이나 풍속이 크게 변할 수 있다. 따라서 측풍이 불어올 때, 활주로 주변 시설물에 의한 유동변화가 항공기의 이 착륙 비행 안정성에 미치는 영향이 고려되어야 하다. 본 연구에서는 3차원 형상의 활주로와 주변 시설물을 2차원으로 가정하여 활주로 주위 유동해석을 전산유체역학을 통해 계산하고, 유동변화가 이 착륙하는 비행기에 미치는 영향을 알아본다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.699-709
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• 2014

This paper proposes a new method for predicting the derailment of a running train under cross-wind conditions, using the single wheelset derailment theory. The conventional theories used for predicting the derailment due to cross-winds were developed under the assumption that derailment will always be of the roll-over type, thus neglecting other possible types such as wheel-climbing, which may occur under special driving conditions. In addition, these theories do not consider running conditions such as dynamic wheel-rail interactions and friction effects. The new method considers the effects of dynamic wheel-rail interaction as well as those of lateral acceleration, rail cant, and cross-winds. The results of this method were compared and verified with those of the conventional methods and numerical simulations.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.251-256
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• 2008

The experimental analysis on a ducted fan for the propulsion system of a small UAV were performed. To investigate the aerodynamic characteristics of the ducted fan, flow fields at inlet and outlet were measured using a hot-wire anemometry. Thrusts were measured with the six-component balance with due regard to the cross wind. To reproduce the cross wind effect, the ducted fan was aligned to $90^{\circ}$ rotated direction against flow direction in the wind tunnel. In this paper, the variation of the flow fields and thrust according to the cross wind were analyzed.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.2
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• pp.63-68
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• 2017

In the present study, a wind tunnel test for a rotor-blade configuration was conducted to investigate a basic aerodynamic performance and a effect of the cross wind. The diameter of the configuration was 1.46 m and the test was carried out for both a clean and a tripped configurations. The boundary layer for the trip configuration was simulated by zig-zag tape and the test performed on constant-velocity and constant-rotational modes. It was shown that the test result for the tripped configuration reduces the maximum power coefficient by 9.4% ~ 12.1% compared to the clean one. Within $5^{\circ}$ of the flow angle, there is no significant loss of power, however, the coefficient is reduced by 5.3% ~ 36.7% in the range of $10^{\circ}{\sim}30^{\circ}$.

• Proceedings of the KSR Conference
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• 2006.05b
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• pp.1209-1214
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• 2006

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.9
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• pp.708-713
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• 2013

KARI is developing a solar-electric powered HALE UAV(EAV-3). For demonstrating the technology, EAV-2H, a down-scaled version of EAV-3, is developed and after EAV-2H's initial flight test, the directional stability and control need to be improved. Thus, the vertical tail and rudder of EAV-2H are redesigned with Advanced Aircraft Analysis(AAA). Size of the rudder is increased from mean chord ratio of rudder to vertical tail, $C_r/C_v(%)=30$ to $C_r/C_v(%)=60$ and size of the vertical tail is reduced 15%. As a result, the directional control to side wind($v_1$) is improved to sideslip angle, ${\beta}(deg)=25^{\circ}$ and $v_1(m/sec)=3.54$. Also, variation of airplane side force coefficient with sideslip angle ($C_{y_{\beta}}$) and variation of airplane side force coefficient with dimensionless rate of change of yaw rate ($C_{y_r}$) are reduced 15% and 22%, respectively to minimize the effect of side wind. The empennage design of EAV-2H is verified with flight tests and applied to design of KARI's solar-electric-powered EAV-3.

• Journal of computational fluids engineering
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• v.1 no.1
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• pp.71-80
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• 1996

An iterative time marching procedure for solving incompressible turbulent flow has been applied to the flows around a high speed train including cross-wind effects. This procedure solves three-dimensional unsteady incompressible Reynolds-averaged Navier-Stokes equations on a non-orthogonal curvilinear coordinate system using first-order accurate schemes for the time derivatives and third/second-order accurate schemes for the spatial derivatives. Turbulent flows have been modeled by Baldwin-Lomax turbulent model. To validate present procedure, the flow around a high speed train at zero yaw angle was simulated and compared with experimental data. Generally good agreement with experiments was achieved. The flow fields around the high speed train at 9.2°, 16.7°, and 45° of yaw angle were also simulated.

• Proceeding of EDISON Challenge
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• 2016.11a
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• pp.1-3
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• 2016

대형 화물 트럭(heavy-duty truck)은 화물 적재에 용이하지만, 공기역학적으로 불리한 형상을 가진다. 이러한 단점을 극복하고자 대형 화물 트럭에는 공기저항력(aerodynamic drag)을 줄일 수 있는 여러 가지 장치가 달려있다. 본 논문에서는 디플렉터(deflector) 형상이 항력 감소에 어떠한 영향을 주며, 평판 형태와 굴곡진 형태의 디플렉터 형상에 대한 항력 계수 비교를 EDISON-CFD를 활용하여 비교하였다. 해석 결과, 측풍(side-wind)의 영향을 무시하며 차량 속도 95 km/h로 등속을 유지하는 조건에서 평판 형태의 Model 1과 바깥으로 굴곡진 Model 2에서 전체 항력 계수가 낮게 나타났다.

• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.179-189
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• 2012

The aim of this paper is to research the change in the turbulent flow and the AOA(Angle Of Attack) occurred by $40^{\circ}$ crosswind to the direction of runway through the three-dimensional numerical analysis and to predict the take-off and landing flight stability. As a result, the maximum amplitude of AOA variation on runway reached $2^{\circ}$ within 3 second because of the wake formed by the constructions in the vicinity of the airport, and the overall effects appeared as an irregular aperiodic forms. Additionally, it was observed that the layout and shape of the buildings effected on the strength of turbulence directly, and the rapid flow generated between the buildings changed into stronger wake and eventually expected that the flow raises serious take-off and landing flight instability.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2017.11a
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• pp.65-66
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• 2017

바람은 기상, 기후, 농림, 교통, 산업, 재난, 생활안전, 신재생 에너지 등 다양한 분야에서 널리 활용되는 요소 중 하나이다. 특히, 항공기 이착륙에서는 측풍의 형태가 항공기 안전에 큰 영향을 미친다. 본 연구에서는 연구지역의 기 구축된 자동기상관측장비(AWS)의 정보를 연계 구축하여, 풍향과 풍속을 1분 단위의 변화량을 반영한 실시간 바람정보 표출시스템을 개발하였다. 이를 통해 기존 문자 및 이미지 형태의 정보에서 시각화된 실시간 바람지도 제공을 통해 공항 이착륙시 항공기 안전운항에 도움이 될 것으로 기대된다.