• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.1-10
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• 2003

An airship is statically unstable, because it has no wing, comparatively small tail and large hull. Hence, an accurate prediction of dynamic stability is critical. In this study, dynamic stability data of the Mid-Size Airship is acquired through forced oscillation wind tests. The test was done in BAR LAMP which is Birhle Applied Research Inc's facility located in Germany. The test was composed with 16 static runs and 26 dynamic runs. As a result, dynamic characteristics of the airship depends on sideslip angle, angular rate and its direction as well as angle of attack. Generally, it is obtained that 3 directional moments have damping, but normal force, side force, and cross-derivatives are unstable. The dynamic derivatives are not sensitive to control surfaces, but have nonlinear dependency on sideslip angle.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.4
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• pp.328-336
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• 2008

The shock tunnel as a hypersonic ground test facility was designed, constructed and its performance test was conducted to reproduce the high speed flow which the hypersonic propulsion system is encountered. The design points were understood and the conceptual design was completed using the quasi one dimensional operation analysis code. After that, the specific performance and compartment design were completed using CFD simulation as the part analysis. The facility was then constructed according to those design results and the performance test was conducted for various operation conditions. In this paper, we suggested the compartment design method using CFD analysis, construction process and various performance test results in detail.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.717-722
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• 2010

Supersonic/Hypersonic wind tunnel is a facility which is intended to test and to observe the physical phenomena around a model by creating supersonic flow in the test section. In designing an airplane, the wind tunnel test is demanded to analyzing aerodynamic characteristics of the model without making a prototype. In this research, the model aerodynamic facility(MAF) is modified for the purpose of increasing running time and its functionality. New pneumatic valves for remote control was installed for safety requirement, and new air tanks was installed on MAF as well. A pipe system is also modified to use those new valves and tanks, and the ceiling and side glasses of the test section are switched to ones with the larger surface area. After the MAF modification, a test is performed at Mach 2, 3 and 4. In this test, shadow graph technique, one of the flow visualization methods, is used to visualize supersonic flow field. The pressure in the settling chamber and working section at Mach 2, 3 and 4 was measured in each case. As a result, the possible model size and running time are obtained.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.7
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• pp.497-505
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• 2022

Performance and hub vibratory load analyses for a lift-offset coaxial rotor are conducted using a rotorcraft comprehensive analysis code, CAMRAD II. The lift-offset coaxial rotor is trimmed to match the total rotor thrust(lift-offset coaxial rotor's thrust) or the individual rotor thrust(upper and lower rotor thrusts, respectively) in this study. The individual rotor's lift and torque, and effective rotor lift to drag ratio for the total rotor are investigated for various advance ratios and lift-offset values. The two result sets with different trim methods are similar to each other and they are correlated well with the wind-tunnel test results. Therefore, the present study using CAMRAD II validates successfully the aeromechanics modeling and analysis techniques for the lift-offset coaxial rotor.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.8
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• pp.129-137
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• 2004

A small size - low priced supersonic wind tunnel of which test section size is 30mm by 35.6mm and run time is 20sec is developed. This educational supersonic wind tunnel is an intermittent blowdown type with an exchangeable nozzle block. In this study, the proper sized and low priced commercial parts are used to reduce the total cost of supersonic wind tunnel. A nozzle design and small supersonic wind tunnel design process has been established, and it is confirmed that a given supersonic flow field has been obtained and proved by experiment.

• Journal of Aerospace System Engineering
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• v.14 no.spc
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• pp.39-48
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• 2020

This paper deals with the process of estimating the environmental noise generated from the actual flying aircraft using the noise measurement results obtained through the wind tunnel test and verifying it through flight tests. In order to evaluate the environmental noise of an aircraft, noise tests and evaluations are generally conducted according to the procedures prescribed by the International Civil Aviation Organization (ICAO). In this paper, we introduced environmental noise evaluation method that can be applied to composite both fixed-wing aircraft and multi-copter, and introduced the evaluation method by experiment. This paper introduces the process of simulating the noise test results measured in the wind tunnel test using real flight test results. In addition, in consideration of flight operating conditions and noise measurement methods proposed by the ICAO, the effective perceived noise level (EPNL) was predicted by performing both the wind tunnel test and the aircraft flight test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.4
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• pp.53-63
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• 2002

The high speed wind tunnel test for the study of the basic aerodynamic characteristics of the rocket with twin strap-on boosters was performed using ADD trisonic wind tunnel on the Mach number range of 0.4~4.0. The 6 % scale model of the early design version of Korean sounding rocket was tested. The tested configurations were core only, core/fins, core/boosters and core/boosters/fins. The effects of core length, gap between core and booster, and bank angle were investigated.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.1
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• pp.91-98
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• 2011

In this study, we measure the aerodynamic forces acting on an AREX train in a crosswind by wind tunnel testing. A detailed test model scaled to 5% of the original and including the inter-car, under-body, and the bogie systems was developed. The aerodynamic forces on the train vehicles have been measured in a 4 m $\times$ 3 m test section of the subsonic wind tunnel located in Korea Aerospace Research Institute (KARI). The aerodynamic forces and moments of the train model on two different track models have been plotted for various yaw angles, and the characteristics of the aerodynamic coefficients have been analyzed at the experimental conditions.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.3
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• pp.230-236
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• 2012

The purpose of this research is to determine the calibration constants of the wind speed measurement systems required to calculate the wind tunnel velocity in the test section. In the present work, the aerodynamic calibration tests of the test section were conducted in the Agency for Defense Development's Low-Speed Wind Tunnel. The test speed ranged from 10 to 100 m/s with a reference pitot-static pressure probe. The validity of the calibration results was evaluated by comparing them with the previous calibration constants. The calibration results show that fair to good agreement is obtained with resonable accuracy.

• Journal of the Korea Society for Simulation
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• v.28 no.1
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• pp.49-56
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• 2019

In this study aerodynamic characteristics of guided gliding type ammunition were investigated by using a computational analysis and wind tunnel test. Missile DATCOM, a semi-empirical method, and a FLUENT, a computational fluid dynamics analysis program, were used for computational analysis. For a guided gliding type ammunition, aerodynamic characteristics were investigated by calculating lift force, drag force, pitching moment and etc. Aerodynamic characteristics of guided gliding type ammunition are completely different from those of conventional ammunition. The results obtained from the computer analysis are similar to those obtained from the wind tunnel test. Although the pitch moment values obtained by the semi-empirical method were slightly different from the wind tunnel test results, the overall computer analysis results showed trends and values similar to the test results. In this study, aerodynamic characteristics of guided gliding type ammunition were identified and it found that semi-empirical method can be applied to analyze the aerodynamic characteristic in the initial design of guided gliding ammunition.