Affiliations: Marine Transportation and Safety Dept., Maritime and
Ocean Engineering Research Institute, KORDI, Jang-dong 171, Yuseong-gu,
Daejeon, 305-343, Korea. E-mail: ppaik@moeri.re.kr | Department of Mechanical Engineering, Pohang
University of Science and Technology, San 31, Hyoja-dong, Pohang, 790-784,
Korea
Abstract: The inflow ahead of a rotating propeller attached to a container
ship model was visualized using a two-frame particle image velocimetry (PIV)
technique. For illuminating the inflow region, a transparent window was
installed at the stern of the ship model. Ensemble-averaged mean velocity
fields were measured at four different blade phases under the design loading
condition. The characteristics of the inflow in the upper plane above the
propeller axis are quite different from those below the propeller axis. In the
far upstream region above the propeller axis, most of the inflow comes from the
hull wake and the axial velocity is very small. As the inflow moves toward the
propeller plane, its axial velocity component increases rapidly. In addition,
the variation of the inflow characteristics with respect to phase angle becomes
apparent. The thick hull boundary layer and out-of-plane motion resulting from
the propeller rotation produce a large turbulent kinetic energy around the tip
of the propeller blade in the upper inflow region. The axial velocity
distribution of the propeller inflow is asymmetric with respect to the vertical
center axis, exhibiting different axial velocities on the port and starboard
sides.
Keywords: Two-frame PIV, Propeller inflow, Phase-averaging, Tip vortex, Total velocity
