抄録
In boundary layer calculations, some assumptions or empirical formulas are usually used. Most of them are based on the experiments of two-dimensional flow or three-dimensional flow with small crossflow angle. Therefore, the experimental studies of ship boundary layer flow and the re-examination of the assumptions are necessary to make the further progress in applications of the three-dimensional boundary layer theory. Using a double model of tanker ship of 1.25m in length, experiments were made under the submerged condition and Reynolds number was kept 10^6. The analyzed results are as follows. (1) The static pressure across the boundary layer varies in regions where the curvature is significant and the boundary layer thickness is large. This can be mainly referred to the effect of centrifugal force. (2) The static pressure on the surface of aft part does not recover due to the displacement effect of boundary layer. (3) The velocity profile in the boundary layer can be represented by Mager's formula or Coles' wall-wake law except ship stern region. But in the stern region it can not be represented satisfactory by these formulas because large crossflow angle and reverse crossflow can be found there. (4) The local skin friction in the direction of potential flow streamline can be represented by Ludwieg-Tillmann's formula. (5) Head's mean curve of the entrainment is examined to be valid for ship boundary layer expect the stern region. (6) The first approximate boundary layer equations, where the effects of centrifugal force and displacement are neglected, are solved numerically in integral form. The calculated boundary layer characteristics, momentum thickness shape parameter and crossflow angle, are compared with measured. They yield fairly good agreements except near the ship stern. (7) Further improvement of the boundary layer calculation, especially near the ship stern, may be expected by taking account of the effects of centrifugal force and so on.
