肥大船の伴流分布
1966 年 1966 巻 120 号 p. 1-9
詳細
1966 年 1966 巻 120 号 p. 1-9
This paper deals with the problem on flow fields around the stern of full ship forms and the estimation of ship wake from model data.
The first part of the paper concerns the measurements of wake in full models and the discussions on the characteristics of flow fields. Wake and pressure were measured by Pitot tube rake and potential wake was separated by measuring wake in models towed astern. Flow observation by tufts was also carried out. Plateau-type distribution of wake and the existence of cross flow and two weak vortices at both sides of the propeller shaft seem to be main characteristics of flow fields in the stern of full forms. Discussion was made on the existence and the cause of cross flow.
The seocond part is on the extrapolation of model wake to full sized ships. Assuming linear superposition of frictional and potential wakes and also similarity of velocity distribution in frictional wake between models and ships, an estimation of ship wake was attempted from the measured model data. Some secondary corrections such as the variation of potential wake between models and ships due to the difference of viscous displacement effect were also considered. Results were shown in the form of wake contours. A comparison of wake shows good agreement between the estimated value and the one obtained from the ship trial analysis.
