A study on efficient recovery method of microplastics using hierarchical vortex clustering

Reference No.	2023a018
Type/Category	Grant for General Research- Short-term Visiting Researcher
Title of Research Project	A study on efficient recovery method of microplastics using hierarchical vortex clustering
Principal Investigator	Kazuo Matsuura（Ehime University, Graduate School of Science and Engineering・Associate Professor）
Research Period	November 21,2023. ～ November 22,2023. February 29,2024. ～ March 1,2024.
Keyword(s) of Research Fields	Microplastics, Marine Debris, Fluid Mechanics, Vortices, Clustering, Compressible Navier-Stokes Equations
Abstract for Research Report	Worldwide, at least 8 million tons of litter is discharged into the ocean each year, with 20,000 to 60,000 tons of that occurring in Japan (J.R. Jambeck, et al., Science, 2015). Marine debris has negative impacts on many areas, including ecosystems, fisheries, tourism, and shipping. It is difficult to collect microplastics (MPS), which have been reduced to less than 5 mm in size by mechanical destruction caused by ultraviolet light and ocean currents, and are easily taken up by living organisms. The applicant faces the Seto Inland Sea. The Seto Inland Sea, which the applicant faces, is surrounded on all sides by the land of Shikoku, Kyushu, and Honshu, which makes it easy for garbage to accumulate, but it also has a globally beautiful landscape dotted with many islands, some 700 in size, and a thriving fishing industry. Although it is necessary to protect the marine area, an effective method for collecting MPS has not yet been established. This study will investigate a new method to efficiently collect and remove this MPS. We will conduct Large-Eddy Simulation of microplastic dispersed ocean currents in the Seto Inland Sea, and from the results, Lagrangian Coherent Structure (LCS) analysis and hierarchical vortex clustering analysis will be conducted to determine where microplastics tend to be concentrated on the ocean surface and in the interior. The results of Lagrangian Coherent Structure (LCS) analysis and hierarchical vortex clustering analysis will be used to determine where microplastics tend to concentrate on the ocean surface and interior, and where and when they can be collected efficiently. Through these studies, we will consider how to make the Seto Inland Sea a cleaner, safer, and more secure sea of marine resources.
Organizing Committee Members (Workshop) Participants (Short-term Joint Usage)	Kazuo Matsuura（Ehime University・Associate Professor） Yasuhide Fukumoto（IMI, Kyushu University・Professor）