Author(s): Jenn Wei Er
Linked Author(s): Jenn Wei Er
Keywords: Particle cloud, thermal, plume, clump
Abstract: With the continuous growth of population and economy in major coastal cities around the world, dredging and land reclamation have become two key activities to improve or maintain the navigation channels for maritime industry and to expand the land for infrastructure development. Both involve the open-water disposal of sediments either during the management of dredged material or during reclamation of the coastal area. The major concerns with the open-water sediment disposal include the loss of suspended sediments and/or associated contaminants into the ambient and the accuracy of sediment placement. Therefore, it is essential to analyze the near-source sediment dynamics for engineering assessment. In literature, the disposed sediment cloud is usually modeled as a group of dense particles released instantaneously into water forming a circulating vortex cloud, which descends through the water column as a thermal. However, this may not be the actual physical configuration. When the sediment volume is significant and requires a finite duration to be fully released, the sediment cloud appears as a starting plume with a thermal-like front head followed by a trailing stem instead. Also, even when the discharge volume is small enough to be treated as an instantaneous release, the formation of sediment clumps has been observed rather than the thermal if the source cloud number is below a certain threshold. The present study establishes for the first time a classification scheme based on physical length parameters to systemically categorize and analyze the different processes depending on the source conditions. The derivation of physical length parameters in the classification scheme is also discussed in the paper
Year: 2017