• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.3
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• pp.175-183
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• 2021

This paper studies measurement of sonic boom created by supersonic flight and its arrival angle estimation techniques. Since sonic boom propagates as an impulsive noise and includes infrasound frequency, we propose measurement instrumentation acquiring sonic boom signature without distortion. And we suggest the methodology for an arrival angle estimation with its performance analysis in accordance with sensor array configurations. The performance of our estimator is verified by comparing theoretical performance bound with statistics of its Monte-Carlo simulation results. Furthermore, we presents the analysis of the sonic boom measurement from real flight tests. This work provides an intuitive concept for sensor array configurations and measurement instrumentation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.7
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• pp.497-504
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• 2020

A technique was developed for analysis on sonic boom created by supersonic flight and for prediction of its sound level and atmospheric propagation characteristics. It is of great importance to anticipate sound level of sonic boom because it causes environmental issue. For that purpose, the simplified sonic-boom prediction method was applied to calculate sound pressure according to physical properties and flight information of the object and distance to measurement site, in this study. Propagation characteristics of shock wave emanated from a flying object was analyzed by using line-of-sight vector and ray tracing method which dealt with refraction of wave due to atmospheric density distribution along altitude. Predicted results agreed well with measured data from real flight.

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.425-430
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• 2013

본 연구에서 전산유체해석 프로그램인 EDISON_CFD를 이용하여 차세대 항공기 날개 형상으로 각광받고 있는 초음속 비행조건을 갖는 Busemann 형식의 복엽기 형상에 대한 공력특성을 연구하였다. 날개는 압축성 조건에서 2차원 에어포일로 간략화 하여 모델링하였으며, 마하수에 따라 발생하는 충격파와 팽창파의 상호작용을 통한 소닉붐의 감소 형태를 분석해 보고, 마하수에 따른 항력계수를 얻어내었으며, 익형과 항력계수, 소닉붐의 상관관계를 분석하여 초음속항공기에서 복엽기 형상이 가지는 장단점에 대하여 연구하였다.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.369-378
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• 1998

When a high-speed train enters a tunnel, a compression wave is generated ahead of the train and propagates along the tunnel. This wave subsequently emerges form the exit portal of the tunnel, which causes an impulsive noise. In the present study, experimental investigation is carried out on the sonic boom noise with parameters of train speed, blockage ratio, nose shape of train and airshaft. These experimental results show that several countermeasures could be used to efficiently reduce the sonic boom. In addition, numerical analysis is performed to predict the sonic boom. The predicted sound waves are in a good agreement with the experimental results.