Abstract
In recent years, dramatically increases in ship dimensions and installed engine power, introduction of new type of special purpose ships and use of roll-on/roll-of, ferries, container ships can cause damage which in many cases threatens to undermine berth structures. Vessel jets of these types of ships can change flow area and cause erosion and scour around foundation of berth structures. Due to the damages in berth structures maintenance and repair cost may increase and also cause management losses. For this reason vessel jet induced the flow area around the berth structures during ships berthing and un-berthing operations are extremely important factor for the port structure design. This study is related with investigation of the flow characteristics at the sea bed around the pile, experimentally. Vessel jets were simulated both as circular wall jet and also propeller jet. The objective of this study is to determine the sea bed shear stress and velocity profiles along the jet axis for open type wharf structures (around a cylindrical piles and also on the slopes). Hot film anemometers were used to measure the magnitude of the bed shear stresses. The results from propeller jet experiments explained the erosion over the slopes. Bed shear and velocity profile measurements were carried out on the rigid bed conditions.
Highlights
The problem of propeller jet induced erosion has significantly risen during the last three decades due to the increase of maneuverability of the ships
The decrease is faster for the conventional propeller jet
Measurements show that vertical velocities along the jet axis increase away from the pile at upstream of the pile, decrease away from the pile at downstream of the pile for the wall jet
Summary
The problem of propeller jet induced erosion has significantly risen during the last three decades due to the increase of maneuverability of the ships. The propeller induced scour need to be considered in the design of the quay structures. There are two main types of trust systems (Fig.1): Propellers (conventional propeller, azimuthal system and bow thruster). Hydro jet Erosion caused by strong flows generated by vessel propulsion systems have become significant importance to protect the bed around the piles and in the design of armoured slopes under open piled quay structures. Velocities at propeller jets at the exits of propellers can be 11 to 12 m/s with resulting bed velocities from 3 to 4 m/s. The average depth of scour could reach as much as 0.5m per month and may be more
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
