To predict the pressure fluctuation induced by propeller sheet ca

To predict the pressure fluctuation induced by propeller sheet cavitation, a modern acoustic methodology is applied. The pressure fluctuation Bortezomib datasheet induced by propeller cavitation is generally known to be proportional to

the second time derivative of the cavitation volume variation and inversely proportional to the distance from the sources, as shown in Eq. (1) (Blake, 1996). equation(1) p′(r,t)=ρ0Q¨(t−r/c)4πr=ρ0(R2R¨+2RṘ2)r However, Eq. (1) is only valid where the pressure fluctuation sources are stationary and the observer is far away from the sources (r  ≫≫R). Moreover, the distance between the rotating propeller and the hull is smaller than the length of the pressure waves induced by the propeller sheet cavitation. Pressure fluctuation can be affected by the sheet cavitation motion and the near-field effect. Therefore,

Eq. (1) cannot be applied. Nevertheless, it is difficult to find studies in the literature that discuss these problems ( Bark, 1988). Therefore, this study applies the combined hydrodynamic and hydroacoustic method to the prediction of the pressure fluctuation caused by a volume variation in the propeller sheet cavitation, which has a dominant effect on pressure fluctuation. Theoretical and numerical approaches considering the source motion and the near-field effect due to the rotation of the sheet cavitation are attempted. The findings will improve studies on hull pressure fluctuation in the future. The paper learn more is organized as follows. Section 2 presents the time domain method for the prediction of the pressure fluctuation and its numerical simulations. Section 3 describes the pressure fluctuation experiments that were performed in the MOERI cavitation tunnel and presents a comparison of the results of the experimental data and the newly developed time domain prediction Arachidonate 15-lipoxygenase results. Potential based

vortex lattice method is coupled with acoustic analogy method for the prediction of pressure fluctuation. The vortex lattice method performs analysis of propeller performance and cavitation volume variation. In the vortex lattice approach the continuous distributions of vortices and sources are replaced by a finite set of straight line elements of constant strength whose end points lie on the blade camber surface. (Carlton, 2007) A potential based lifting surface methods and their application to propeller technology began in the 1980s. A lifting surface method for marine propeller was developed by Kerwin and Lee (1987) at the Massachussetts Institute of Technology. The fundamentals and details of lifting surface method are well described in works of Lee (1979, 1992) and Kinnas and Fine (1992). Potential based flow analysis and pressure fluctuation prediction method are widely used in propeller design. These numerical methods are developed in MOERI in 1990′s.

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