Meandering Morphodynamics and Related Fluvial Processes

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This research program aims at advancing the understanding and analytical treatment of flow and sediment transport processes in straight and meandering rivers, leading to an improved mathematical modelling of key large-scale processes taking place in such rivers. ******Over the next five years, the research will be carried out along two themes: the dynamics and modeling of the planimetric evolution of meandering streams (Theme A) and large-scale turbulence (Theme B). The research under Theme A focuses on overcoming unresolved issues related to the modeling of meandering flow and its interaction with the stream movable boundary. Under Theme B, the knowledge on large-scale turbulence will be extended to include a first understanding of the dynamics and morphological consequences of large-scale horizontal coherent structures. The specific objectives are as follows: (1) to develop an efficient 2-D hydrodynamic model for the computation of meandering flow, including appropriate parametrizations of three-dimensional effects; (2) to develop new analytical formulations of bank erosion; (3) to develop a numerical model for the computation of long-term planimetric evolution of meandering streams, and use it to test, refine and validate the new formulations of flow and bank erosion resulting from research carried out under objectives 1 and 2; and (4) to penetrate the dynamics of the life-cycle of large-scale turbulence horizontal coherent structures occurring in straight or nearly straight streams, and gain insight into their morphological consequences.******For the present purposes, extensive series of laboratory experiments will be conducted in large-scale facilities, including two different 1 m wide, 50 cm deep channels formed by three consecutive meander loops for the meandering studies, and a 21m-long straight flume with adjustable width from 1 to 2m for the turbulence studies. State-of-the-art equipment will be used to obtain detailed records of bed and plan shape morphological adjustments, and measure instantaneous and time-averaged flow velocity fields, and local sediment transport rates. Field data from the literature and unpublished data available from water-related agencies will be gathered, to get further insights into the processes under investigation and enable further testing of the computer models resulting from this research.******The new knowledge and tools resulting from the proposed research will be directly applicable to the feasibility analysis, design and optimization of an extensive array of river engineering studies and projects and the development of sound river management guidelines and protocols. The research will result in the training of 5 PhD, 2 MSc and 3 BSc students, who will acquire highly desired, advanced skills in hydraulic physical and numerical modeling, and a deep appreciation of the social, economic and environmental aspects of river engineering and management. *****