| Summary: | During mooring operations, ships tend to make an extensive use of bowthruster in order to minimize the need for tug assistance. Jet caused by transverse thrusters directly impinges quay walls, and can cause scour on the bed, therefore threatening structural stability of quay walls. Presence of vertical quay walls induces reflection of bowthruster's jet, further complicating the already complex flow field. Despite extensive research has been conduced on free flow, several knowledge gaps are still present regarding propeller induced flow when confined, for instance by a vertical quay wall. In this research, focus is on flow field on the bottom of a vertical quay wall induced by channel-type bowthrusters, which are commonly used for inland vessels. Field measurements have been conducted at the Antarcticakade, Ports of Rotterdam, using inland vessel MTS Vorstenbosch. The vessel is equipped with a 4-channel Veth Jet type bowthruster system. Use of a combination of Acoustic Doppler Velocimeters and Acoustic Doppler Current Profilers allowed measurements of flow velocities on the bottom of the quay. Data from the measurements has been analysed to investigate influence of distance between outlet and quay wall, and keel clearance, on the flow pattern at the bottom. Results have then been contextualized within the literature framework, and their impact on design of bottom protection according to most used guidelines has been assessed. The results of this field measurement showed mean flow velocities near the quay wall generally in the order of magnitude of 1 m/s, with the exception of one test, where mean flow velocities in the order of magnitude of 2 m/s were recorded. This relatively low mean flow velocities were often correlated with large turbulent fluctuations, leading to values of relative turbulence intensities higher than the ones found in literature, and sometimes even equal to 1. Comparison with the theoretical calculations of velocities according to Dutch and German methods suggested by PIANC, showed both ...
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