Physical and numerical modelling of sediment transport in the surf zone

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The present research theme aims to reducing uncertainties concerning the mechanisms through which non-cohesive sediments (sand particles) are being displaced, transported and deposited in the form of bedload in the surf zone, due to intense turbulence generated by wave breaking. This is an essential step in constructing a practical engineering tool - in the form of Numerical Beach Morphodynamic Model - capable of predicting the time and space evolution of the coastline.    The major zone of intense sediment agitation is known as the surf zone. This physical domain is located between the first wave breaking line and the shoreline and is characterized by intense wave agitation and currents associated with it (rip currents, longitudinal currents, undertow, etc) which represent the driving mechanism for sediment displacement. The analysis of sediment transport will focus on the area close to the seabead (Wwave Bottom Boundary Layer, WBBL).  The current work will include both laboratory work and mathematical and numerical modeling. Three main topics will be investigated under the current research: 1. The qualitative and quantitative analysis of the sediment entrainment and displacement in the area close to the seabed due to wave-induced turbulence under irregular wave conditions. This task will include sediment particles velocity and concentration measurements. 2. Formulation of a new numerical model for the WBBL which would realistically reflect the physics of the inception and devleopment of the sediment movement. A new definition for the reference level (inside the BBL layer) will be incorporated together with the inclusion of the inertial effects affecting the sediment particle in motion.    The research project will enable the training and formation of graduate students towards becoming highly skilled hydraulic engineers and future researchers and/or designers.