Journal of the Korean Society of Manufacturing Technology Engineers (한국생산제조학회지)

The Korean Society of Manufacturing Technology Engineers (한국생산제조학회)
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Experimental comparison on the noise characteristics of free and impinging jets

자유분류와 충돌분류의 소음특성에 관한 실험적 비교

  • 이동훈 (서울산업대학교 기계공학과)
  • Published : 1996.06.01
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Abstract

The objective of this study is to find experimentally the characteristics of the noise generated by the impinging jet on the normal plate, and also to compare the noise characteristics of the impinging jet with those of the free jet. The experiment is performed for the measurement of the noise specturm, the noise power, and the directivity for the free and impinging jets. From the experiment. it is found that the power of noises generated by the free jet as well as the impinging jet is proportional to the eighth power of the jet velocity through the circular converging nozzle, and that the noise power of the impinging jet is 15dB as high as one of the free jet when the plate distance is about within one to three times the nozzle diameter at the pressure ratio 1.39. The sound pressure level of the impinging jet depends upon the jet pressure and the plate distance. The plate distance with the maximum overall sound pressure level is increased with the jet pressure. The directivities with 1/3 octave band frequency for both the free jet and the impinging jet are greatly influenced by the convection effect.

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References

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