• Title/Summary/Keyword: 프로펠러 명음

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A study on the identification of underwater propeller singing phenomenon (수중 프로펠러 명음 현상의 규명에 관한 연구)

  • Kim, Taehyung;Lee, Hyoungsuk
    • The Journal of the Acoustical Society of Korea
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    • v.37 no.2
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    • pp.92-98
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    • 2018
  • This paper is a study on the generation mechanism of propeller singing based on the cavitation tunnel test, underwater impact test, finite element analysis and computational flow analysis for the model propeller. A wire screen mesh, a propeller and a rudder were installed to simulate ship stern flow, and occurrence and disappearance of propeller singing phenomenon were measured by hydrophone and accelerometer. The natural frequencies of propeller blades were predicted through finite element analysis and verified by contact and non-contact impact tests. The flow velocity and effective angle of attack for each section of the propeller blades were calculated using RANS (Reynolds Averaged Navier-Stokes) equation-based computational fluid analysis. Using the high resolution analysis based on detached eddy simulation, the vortex shedding frequency calculation was performed. The numerical predicted vortex shedding frequency was confirmed to be consistent with the singing frequency and blade natural frequency measured by the model test.

Noise-Vibration Phenomenon inducing Propeller on the 55ft Class Sailing Yacht (55피트급 세일링 요트의 프로펠러 유기 소음·진동 현상)

  • Lee, Donchool;Kim, Hobin;Eam, Gitak
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.10a
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    • pp.753-756
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    • 2013
  • The demand for sailing yacht is increasing in consonance the improvement of people's live. These yachts can be dually propelled by wind and by diesel engine power. A singing (humming, whistling) phenomenon induced on the propeller was discovered on a 55-foot catamaran sailing yacht. As a result, an increase in the structural vibration of the stern tube room and propulsion system with abnormal noise was detected due to this flow. In this study, the cause of the phenomenon is investigated and its possible countermeasures proposed.

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A Study on the Propeller Blade Singing Place of an 86,000 Ton Deadweight Crude Oil Tanker (86,000톤 원유운반선 프로펠러 날개의 singing(명음) 발생위치 조사)

  • Dong-Hae Kim;Kyoon-Yang Chung
    • Journal of the Society of Naval Architects of Korea
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    • v.31 no.3
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    • pp.59-64
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    • 1994
  • A study was conducted to investigate the propeller singing place of an 86, 000 ton Deadweight Crude Oil Tanker. In preliminary study, proper use of finite element analysis was verified by comparing with the result of hammering test in the air. Then the finite element analysis was carried out for the blade in the water and compared with the noise measurement during sea trial, which enabled to confirm the local resonances of blade structure. Result of the study showed that the singing occurred most probably at trailing edges on the blade tip over 95% of propeller diameter. Owing to edge cutting of a successfoul remdial action, the singing excitation forces seemed to be reduced whereas the vibration characteristics of the blade was not changed.

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Localization of Underwater Noise Sources Using TDOA (Time Difference of Arrival) Method (도달지연시간 기법을 이용한 수중 소음원의 위치추적)

  • Ahn, Byoung-Kwon;Go, Yeong-Ju;Rhee, Wook;Choi, Jong-Soo;Lee, Chang-Sup
    • Journal of the Society of Naval Architects of Korea
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    • v.48 no.2
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    • pp.121-127
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    • 2011
  • As considerable interests in noise emission from a ship have been increased, the need for localization of noise sources of the marine propeller generating cavitation and singing noise is looming large. In many practical cases, cavitation and singing noise occur on a particular position of the certain blade of the propeller. It is so important to know the position of noise source correctly in order to eliminate or suppress unwanted noise. In this study, we develop "noise source localization technology" using TDOA method. Experimental measurements carried out at the circulating water channel and towing tank show that noise source can be clearly identified and localized using TDOA method.