Numerical study of propeller slipstream characteristics during berthing and unberthing maneuvers of a RORO vessel

For the investigation of the impact of the propeller slipstream on the port facilities, detailed analyses are carried out using a Reynolds-Averaged Navier-Stokes (RANS) method. The characteristics of the propeller flow field were studied, taking into account operating conditions during berthing and unberthing, interactions with the ship hull, quay wall and harbor bed. To obtain the necessary maneuvering data, information was extracted from the voyage data recorder (VDR) of a twin-screw RORO vessel during berthing and unberthing in the Port of Lubeck- ¨ Travemunde. Automatic identification system (AIS) and ¨ VDR data sets were collected and analyzed to identify conditions of interest for the numerical investigations. The vessel is equipped with two flap rudders and two bow thrusters. RANS simulations were performed for different rudder angles and number of revolutions of the main propellers (MPs) and transverse thrusters (TTs). The simulation results include unsteady velocity and pressure distributions in the flow field near the quay walls and harbor bed, considering different positions and orientations of the ship relative to the quay walls. The calculated maximum axial induced velocities are compared with those obtained using the semi-empirical formulae. In addition, the proper orthogonal decomposition (POD) on the harbor bed was used to evaluate the wall shear stress (WSS) and turbulent kinetic energy (TKE) to identify locations of maximum scour potential. The numerical results were thoroughly evaluated and analyzed to provide a robust basis for future extensions of the semi-empirical formulae.

Subjects

Propeller Slipstream

Harbor Maneuver

RANS Simulations

Maneuvering Devices

VDR-Data

DDC Class

620: Engineering

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publishedVersion

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http://rightsstatements.org/vocab/InC/1.0/

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Wang-NumericalStudyOfPropellerSlipstreamCharacteristicsDuringBerthing-1177-1-final.pdf

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Numerical study of propeller slipstream characteristics during berthing and unberthing maneuvers of a RORO vessel