Abstract

Investigating the propeller load fluctuation in waves is very important to consider ship propulsion performance in waves. Many studies have been done for the propulsion in waves. Some studies exist on prediction of inflow by direct measurement of thrust force or torque; however, some problems regarding measurement phase occur due to the gravity gradient component of the shaft and propeller that affects thrust measurements and response of spring system. The velocity distribution at propeller plane has not been measured in detail due to the difficulty of experiment. On the contrary, with the rapid progress of CFD code the computation of flow field around a moving ship in waves can be possible. But the validation data for detailed flow field is not available. Some phase-averaged flow measurements were done for various conditions, but the flow fields around a ship with motion in waves is not available. So, the phase averaged flow measurement is conducted in this study using stereo PIV system and phase synchronizer with heave motion. In this study, phase-averaged flow field in waves was measured using SPIV system in the towing tank around the KVLCC2 model ship in full load condition which has no appendages, rudder, and propellers. The model tests have been performed at forward speed Fr=0.142 (Re=2.55×106) for three head wave conditions (λ/Lpp=0.6, 1.1, 1.6) and one calm water condition. The fluctuation of propeller plane wake is discussed based on the measured results.

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