http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
오리피스 구조내에서 발생한 공동소음의 음향학적 스케일링에 관한 연구
이재환(J. H. Lee),이승배(S. Lee),유선학(S. H. Yoo) 한국유체기계학회 1999 유체기계 연구개발 발표회 논문집 Vol.- No.-
The major source of noise in the process of transporting liquids is related to the cavitation phenomenon. The control valve noise is mostly dominated by bubble dynamics under cavitating conditions. In this investigation, an orifice configuration is set-up to correlate its flow-field and acoustic signatures with those from a control valve device. The performance and noise characteristics form the orifice configuration in anechoic surroundings were measured to reveal the noise sources depending on pressure differences across the orifice configuration. The sound powers from the orifice configuration are effectively normalized using proposed scaling parameters. Flow-excited dynamic systems for which there is no strong coupling between the flow and the system response can be described using a linear source-filter model. On this assumption, the normalized sound powers can be decomposed of noise source function and a response function. To find noise sources, pressure spectra measured over a range of pressure differences are transformed into the product of two non-dimensional frequency function : Pss(He,fca,x/D) = F(fca) G(He,x/D). This scheme of finding noise sources is shown to be applicable to the cavitation noise from the control valve effectively. Two kinds of cavitating modes based on our experimental data are found and discussed.