抄録
In the previous report, the problem of the leading edge unsteady cavitation on two-dimensional hydrofoils was discussed and some numerical examples were shown. As the result, the so-called hysteresis effect of the unsteady cavity which originates from the inertia of the surrounding water is obtained: 1) The phase delay takes place. 2) The growth of the cavity extent and volume are depressed These results seems to be qualitatively correct. In this report, the unsteady cavity on ship propeller foils are discussed, based on the results obtained in the previous paper. The concept of an equivalent flat foli is introduced and a practical calculation method based on it is established. Numerical examples are shown for the cavitation patterns on foils of ship propellers in wake and compared with the observations. In general, the calculated and observed pattern seem to be in good agreement within the cases reported in the present paper. But the present report includes also an examples to which the basic assumption of the two-dimensional leading edge cavitation for each radial sections becomes invalid in decreasing stage. To treat the case, a different viewpoint would be required. Furthermore, a preliminary result for cavity volume is also obtained, and the suggestion for its effect on hull surface is given. Directions for the future studies are shown in the conclusions of the present paper.
