• Title/Summary/Keyword: 초음속 제트소음

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An Analysis of Supersonic Jet Noise with a Converging-Diverging Nozzle (C-D 노즐을 고려한 초음속 제트 소음 해석)

  • Kim Yong Seok;Lee Duck Joo
    • Proceedings of the Acoustical Society of Korea Conference
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    • autumn
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    • pp.389-392
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    • 2001
  • To investigate the generation mechanism of the shock-associated noise, an underexpanded supersonic jet from an axisymmetic nozzle is simulated under the conditions of the Nozzle exit Mach number of 2 and the exit pressure ratio of Pe/Pe =1.5. The present simulation is performed based on the high-order accuracy and high-resolution ENO (Essentially Non-Oscillatory) scheme to capture the time-dependent flow structure representing the sound source. It was found that the shock-associated noise is generated by the weak interaction between the downstream propagating large turbulence structures of the jet flow and the quasi-periodic shock cell structure during the one is passing through the other. The directivity of propagating waves to the upstream is clearly shown in the visualization of pressure field. It is shown that the present calculation of the centerline pressure distribution is in fare agreement with the experimental data at the location of first shock cell.

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An effect of design parameters of water injection silencer on the characteristics of noise generated by Liquid Rocket Engine (물분사형 소음기의 설계 변수가 액체로켓엔 소음특성에 미치는 영향)

  • Park, Hee-Ho;Cho, Byoung-Sun;Kim, Yoo;Ji, Pyung-Sam;Kim, Seon-Jin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.2 no.2
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    • pp.83-87
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    • 1998
  • To reduce the supersonic jet noise from the liquid rocket engine, water injetion silencers were designed and tested. Test variables were the mass flow rate of water jet, the length of primary pipe and the diameter of expansion pipe. Followings are the results of this study. 1. From the same mass flow rate of water, longer primary pipe was more effective to reduce the noise. 2. Noise level was significantly reduced with increasingly water flow rate. 3. The optimum water flow rate was 10~12 times of the propellant flow rate. 4. By installing expansion pipe, noise level was reduced approximately 30㏈ compared to without expansion pipe

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Experimental Study on Dynamic Behavior of a Titanium Specimen Using the Thermal-Acoustic Fatigue Apparatus (열음향 피로 시험 장치를 이용한 티타늄 시편의 동적 거동에 관한 실험적 연구)

  • Go, Eun-Su;Kim, Mun-Guk;Moon, Young-Sun;Kim, In-Gul;Park, Jae-Sang;Kim, Min-Sung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.2
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    • pp.127-134
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    • 2020
  • High supersonic aircraft are exposed to high temperature environments by aerodynamic heating during supersonic flight. Thermal protection system structures such as double-panel structures are used on the skin of the fuselage and wings to prevent the transfer of high heat into the interior of an aircraft. The thin-walled double-panel skin can be exposed to acoustic loads by supersonic aircraft's high power engine noise and jet flow noise, which can cause sonic fatigue damage. Therefore, it is necessary to examine the behavior of supersonic aircraft skin structure under thermal-acoustic load and to predict fatigue life. In this paper, we designed and fabricated thermal-acoustic test equipment to simulate thermal-acoustic load. Thermal-acoustic testing of the titanium specimen under thermal-acoustic load was performed. The analytical model was verified by comparing the thermal-acoustic test results with the finite element analysis results.