In this paper, we have conducted a wall-resolved large-eddy simulation（WRLES）for a cavitating flow around a Clark Y-11.7％hydrofoil by using two kinds of homogeneous cavitation model, one of which is a typical one-equation model by Okita and Kajishima（OK model）and the other is a four-equation model called multi-process（MP）model. First, we discussed the validity of the present WRLES for the non-cavitating flow, and a reasonable result was obtained under the given boundary condition. Next, it was confirmed that OK model based on the WRLES successfully reproduced an unsteady sheet/cloud cavitation with shedding of a sheet cavity while MP model did not simulate the sheet/cloud cavitation, i.e., the latter model just showed the unsteady change of the sheet cavity length without the shedding. The reason why such sheet/cloud cavitation is not reproduced in MP model might be caused by that the position of the sheet cavity front（inception point）is downstream compared with OK model, whose characteristic in MP model is closer to experiments. Namely, the sheet cavity front in the case of MP model appears downstream from a position of the suction peak pressure while the front position in the case of OK model corresponds to the suction peak as same as other homogeneous cavitation models. Taking account of that the inception point has been experimentally observed at a laminar separation or turbulent transition point appearing downstream from the suction peak, MP model may have a potential for better prediction of the inception point.

The authors developed a new method to analyze underwater radiated noise（URN）by combining the bubble mass distribution（BMD）model with the bubble dynamics and radiation（BDR）model. In this paper, this method was introduced first. As a validation of this method, numerical analysis of cavitation around the Seiun-Maru high-skew propeller II was performed by the BMD model, URN was estimated by the BDR model, and a comparison was conducted between the estimated URN with experimentally-measured URN of the actual Seiun-Maru. Consequently, this method looks very promising.

In this study, unsteady numerical analysis was done for cavitation in liquid hydrogen and nitrogen where thermodynamic self-suppression effect appears. The distribution of turbulent thermal diffusivity was estimated along the cavity surface. Then, it was shown that the turbulent thermal diffusivity coefficient has order of 103, it means that the turbulence has strong influence on the thermal diffusivity around the cavity surface region. Additionally, the scaling law of the averaged turbulent diffusivity coefficient on Reynolds number was obtained from the numerical results. Finally, the turbulent thermodynamic parameter was suggested which was derived by taking account of turbulent effect on thermal diffusivity and the scaling law into the nondimensional thermodynamic parameter and that was validated using the present numerical results.