4.2 Flow Pattern along Ship Bottom
Fig.11 shows the velocity vector, and Fig.12 and Fig.13 show velocity contour of two components Vx and Vy at the design point, respectively. Measured data were obtained by a five-hole Pitot probe, which was traversed in the z- and x-directions (see Fig.2). Presented data here were acquired at the two-intake operation. The traverse plane was located at Δy/B = 0.10 off the wall. On the middle of the two intake ducts (Z = O in Fig.2), Vx component was reduced especially for the flat and flat combination, and the suction effect by both intake ducts is dominant. In case of the flat and tapered combination and two-intake operation, on the other hand, the reduction of velocity component Vx was not clearly observed and the interaction effect between the intake ducts is relatively small. The velocity component Vy also showed the difference of intake effect. In the flat and flat case, Vy showed high velocity in approximately upstream 70% of streamwise length of the inlet of intake duct and showed low velocity just downstream the high velocity region. The influence of intake on main flow along the ship bottom was not so clear in the fiat and tapered case.
4.3 Static Pressure Distribution along the Intake Duct Wall
Fig.14 and Fig.15 show the static pressure distribution along the intake duct wall at two I.V.R. conditions, (I.V.R.)n = 1.0 and 3.0. In these figures, one of the intake duct was chosen in the flat and fiat case, and the tapered intake duct in the flat and tapered case. Measured and predicted results are compared in Fig.14 and the difference in the intake operation was compared in Fig.15. In Fig.14, predicted pressure co-effficients for (I.V.R.)n = 3.0 showed the tendency of lower values just upstream the intake duct exit and just downstream the duct lip. On the other hand, measured results showed lower static pressure at the duct lip and just downstream the duct lip along the ship bottom. Since the mesh generation was performed in a body-fitted manner, it can be said that the difference between measured and predicted values is due to the mesh resolution, turbulence model, numerical scheme and therefore local separation flow pattern around the duct lip. In Fig.15, the static pressure clearly showed lower pressure along the duct wall downstream of the duct lip in case of the two-intake operation than the single-intake operation. It was found that the flow interaction effect led to the reduction of static pressure along the duct wall downstream of the duct lip.
