• Journal of the KSME
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• v.23 no.1
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• pp.8-13
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• 1983

풍동을 이용한 실험실 연구가 직면하고 있는 전반적인 국내의 문제점들은, 첫째, 고가의 품목에 국외 설계제작이 불가한 것으로 인식이 되어있고, 둘째, 카다로그에 의한 외국산의 구입으로 의 도한 실험과 그 실험실 특성에 맞는 제품을 구입하지 못하고 있으며, 셋째, 측정기의 부족을 들 수 있다. 그리하여, -본고에서는 우리가 일반적으로 많이 사용하고 있는 아음속풍동의 다목적 사용 방법을 간단한 예를 들어 설명하고자 한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.4
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• pp.12-17
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• 2004

The PSP technique has been used to measure pressure distribution on model surfaces ins high-speed flows. The objective of this study is to develop a PSP technique which can be applied to low-speed aerodynamic flows. Four different PSP formulations including two porphyrins (PtOEP and PtTFPP) and two polymers (Poly(TMSP) and RTV-118) were tested and the performance of each combination was evaluated. In a static calibration, the luminescent intensity of the PSP coatings was measured from 0kPa to 11kPa with 0.5, 1, 2kPa increments. Among 4 PSP formulations tested, the combination of PtOEP and RTV-118 shows the best performance. The developed PSP technique was applied to an oblique impinging jet to measure the pressure field distribution on the impinging plate.

• Journal of Aerospace System Engineering
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• v.12 no.4
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• pp.57-63
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• 2018

IR thermography is a non-invasive method and used for the visualization of the surface temperature of the model. However, this technique only derives 2D results and not quantitative data. The goal of this study is to apply the 3D mapping technique for IR thermography. The wind tunnel model is an ogive-cylinder with a wind speed of 20 m/s ~ 80 m/s and the angle of attack ranging from $0^{\circ}$ to $90^{\circ}$. The real location of the model was made to correspond with the position of the IR image using the makers. Based on this result, quantitative results were obtained. The 3D mapping method was verified by comparing the separation point and the theoretical value.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.3
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• pp.226-232
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• 2017

Surface pressure distributions over the RAE-A wing-body configuration were investigated and the grid convergence along the streamwise, spanwise, and circumferential directions was numerically studied. Flow analysis in subsonic and transonic conditions was conducted using the $k-{\omega}$ Wilcox-Durbin+ turbulence model. Surface pressure distributions for subsonic flows were well matched, but those for transonic shocked flows showed a little discrepancy with the experimental data. A cubic spline extrapolation method was applied in order to investigate the grid convergence. This method presented that the grid resolution in the circumferential direction is the most important grid parameter. A refined grid system was made based on the grid convergence study and provided more accurate prediction, especially on the symmetric body surface of RAE-A configuration.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.1
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• pp.27-32
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• 2007

this paper the acoustic signature from a supersonic nozzle is measured and compared to the result of a program developed for a gas turbine noise prediction. In order to measure the jet Mach Number, the pressure and temperature at the settling chamber was measured along with pressures from a pitot-tube placed near the exit. The results are also compared to the ones obtained with a shadow graph technique. Jet noise produced by an imperfectly expanded jet contains shock associated noise, which consist of broadband noise and screech tone noise. For subsonic condition, the directivity is dominant to the downstream direction due to turbulence mixing noise. For supersonic conditions, however, the directivity is dominant toward upstream direction due to shock associated noise. The comparison with a jet exhaust noise prediction code shows good agreement at supersonic conditions but needs to be improved at subsonic speeds.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.9
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• pp.773-780
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• 2015

In this paper, the structural integrity for a cylindrical vehicle in subsonic environments is verified. In order to confirm static structural safety for the cylindrical vehicle in extreme maneuver condition, the structure analysis and full-scale static structure test are carried out. The commercial finite element codes, MSC. Patran/Nastran is used for numerical simulation. The full-scale static structure test equipment consists of the counterbalance system, loading system and data acquisition system. Besides, the dynamic characteristics for the cylindrical vehicle are reviewed by performing an impact hammer test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.8
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• pp.702-710
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• 2011

This paper aims to verify the applicability of OpenFOAM, the widely recognized open source CFD code, to external flows commonly found in aeronautical problems. To this end, several representative flow cases are selected first from subsonic to supersonic flow fields. Then, the computational results obtained from OpenFOAM are systematically compared against available data from experiments and other numerical codes. It was found that the strength and location of shock are well predicted and the effects of boundary conditions on the computed results are reviewed. Subsonic flow with massive separation is selected to validate the prediction capability of OpenFOAM. Based on the current results, the limitation and possibility of OpenFOAM was confirmed and for future study using OpenFOAM was suggested.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.295-301
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• 2007

The aeroelastic characteristics of a wing with control surface freeplay are investigated. The transonic small disturbance equation is used for unsteady aerodynamic forces in subsonic/transonic region. The fictitious mass method is introduced to apply a modal approach to nonlinear structural models. Nonlinear aeroelastic time responses are calculated by the coupled time integration method. Using these methods, an efficient aeroelastic analysis is achieved for aerodynamic and structural nonlinearities simultaneously. The effects of the aerodynamic nonlinearity, initial flap amplitude, and freeplay magnitude in aeroelastic characteristics are investigated in this study.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.2
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• pp.130-135
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• 2007

Wind tunnel test for Smart UAV power model has been conducted at KARI LSWT for about 3 months. The static model is used for the base plane and the power effect of tilt rotor is simulated by the tilt-rotor test rig installed in the test section. Although the genuine power effect is the difference between power-on and off tests. The existence of struts for power effect test produced unwanted form of interference and caused the change in flow angularity. To precisely evaluate power effect, a special approach is applied to Smart UAV test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.4
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• pp.123-130
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• 2002

Aerodynamic results for an airplane model produced in a subsonic wind tunnel testing inadvertently include errors which are added during model preparation, data acquisition, manipulation, and/or describing the results. Predicting or analyzing uncertainty for the final results is necessary for trusting them and for applying them to real airplane. This paper describes the analytic and systematic method for calculating and describing the uncertainties of aerodynamic coefficients.