• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.791-796
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• 2000

The cavitation-induced fluctuating pressure of the container ship named "Sydney Express" is measured in Samsung Large Cavitation Tunnel(SCAT). In the measurements, a complete ship model is employed. The effects of thrust coefficient and cavitation number on cavity pattern and cavitation-induced fluctuating pressure were investigated experimentally. It is demonstrated that the fluctuating pressure coefficient is very sensitive to the cavitation number. The results of cavitation and pressure fluctuations are compared with those of ITTC and HSVA, which shows fairly good agreement. It is exhibited that the removal of rudder can significantly change the loading condition of a propeller, and can reduce the fluctuating pressure coefficient almost by half.

• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.44-50
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• 2005

Since a cavitation pattern in model scale can be different from that in full scale, it has been highly demanded to measure a fluctuating pressure induced by propeller in full scale. For the verification of the cavitation test for 105K lanker in the large cavitation tunnel in Samsung Ship Model Basin(SSMB), an effective pressure fluctuation measurement system was developed and a series of full scale measurements was carried out. These results were compared with those of cavitation tests in SSMB. The measured results in full scale gave good agreements to those in model tests. The fluctuating pressure at $2^{nd}$ blade frequency in full scale seems to be highly dependent upon tip loading.

• 대한조선학회지
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• 제22권2호
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• pp.12-26
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• 1985

This paper describes the experimental method to predict the propeller induced fluctuating pressure on the hull surface. Cavitations of the three model propellers with varying degree of skews, $0^{\circ},\;36^{\circ}\;and\;72^{\circ}$, were observed and the fluctuating pressure induced by the cavitating propellers in the flat plate above these propellers were measured simultaneously at 9 points in the wake field generated by the wire-mesh screens. Another model propeller designed for the dummy model ship was tested in a similar way behind the dummy model ship. The effects of skew variation on the cavitation patterns and fluctuating pressures were illustrated, and the influence of tip-clearances on the fluctuating pressures was also demonstrated. As a result, it is shown that the level of fluctuating pressure and cavity extent could be controlled to some extent by introducing the skews and tip clearances.

• 대한조선학회논문집
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• 제30권4호
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• pp.46-60
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• 1993

캐비테이션 터널에서 변동압력의 정확한 계측은 실선에서의 진동과 소음세기 예측에 필요하다. 본문에서는 프로펠러 케비테이션에 의해 야기되는 변동압력의 실험적연구 결과를 나타내고 논의 한다. 문제시 되고 있는 프로펠러 회전수에 의한 영향을 이해하고자 변동압력을 캐비테이션 터널에서 평판을 이용하여 여러 회전수에서 계측 하였다. 균일류에서 오차를 추정하기 위하여 계측 및 계측결과에서의 불확실성 해석이 사용 되었다.

• Journal of Mechanical Science and Technology
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• 제17권8호
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• pp.1203-1210
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• 2003

Emission of ultrasonic vibration to turbulent flow promotes the turbulence generation due to the resonantly oscillating pressure field and thereby induced cavitation. In addition, ultrasonic vibration is well transmitted through water and not dissipated easily so that the micro-bubbles involved in the fluid induce the gaseous cavitation if the bubbles are resonated with the ultrasonic field. In the present study, we found through LDV measurement that the gaseous cavitation induced by ultrasonic vibration to CO$_2$saturated water flow in the rectangular cross-sectioned straight duct enhances turbulence much more than the case of non-ultrasonic or normal ultrasonic conditions without gaseous cavitation. We also found that the fluctuating velocity component induced by emitting the ultrasonic vibration in normal direction of a rectangular channel flow can be redistributed to stream-wise component by the agitation of gaseous cavitation.

• 대한조선학회논문집
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• 제37권1호
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• pp.10-25
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• 2000

모형 프로펠러 날개의 레이놀즈 수와 날개 앞날 표면거칠기 그리고 터널용수의 공기함유량이 모형 프로펠러의 캐비테이션 초기 발생, 캐비테이션 발생량 및 변동압력에 미치는 영향을 캐비테이션 터널에서 실험적으로 조사하였다. 'Sydney Express' 컨테이너선의 모형 프로펠러 캐비테이션 관찰과 변동압력 계측결과를 타 연구기관의 모형실험 결과와 실선 프로펠러의 캐비테이션 관찰 및 변동압력 계측치와 함께 비교하였다. 그 결과 매우 타당한 결과를 보여주었다.

• 대한조선학회논문집
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• 제36권1호
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• pp.47-52
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• 1999

캐비테이션 터널에서 캐비티가 발생한 프로펠러에 의하여 평판에 작용하는 변동압력이 계측정도를 향상시키고, 프로펠러 회전수 영향을 최소화 하였다. Sydney Express선의 프로펠러 변동압력에 대한 타기관의 계측치 특성과 비교한 결과 당 연구소 계측치는 매우 안정적 경향을 보였다. 그리고 모형선과 실선의 변동압력 계측치 및 평판에 작용하는 변동압력 계측치의 크기와 경향을 비교한다. 평판의 변동압력 계측치로부터 실선 변동압력을 추정코자 양력면 이론에 의한 수치계산에 의해 도출된 강체경계율을 적용하여 타당성을 확인하였다.