Variability of sediment processes around a tidal farm in a theoretical channel

Sediment transport plays a crucial role in coastal ecosystems and is one of the least known parameters in high energy sites. The recent development of tidal energy projects challenges the scientific community to better understand this natural phenomenon and the interactions with tidal turbines. Using MIKE21/3 software from DHI, a benchmark for sediment transport model was developed with simulations with and without a tidal farm in idealised two and three-dimensional tidal channels. Results reveal that a 2D approach is sufficient for regional scale morphological assessments, however 3D models allow for a closer examination of influences around the tidal farm. Differences in calculating sediment transport rates based on approaches after Engelund & Freds & oslash;e and Van Rijn formulae illustrate the degree of uncertainty in modelling sediment transport rates. Results for the Engelund & Freds & oslash;e models also show that they are sensitive to mesh resolution in equilibrium conditions and are more stable in non equilibrium conditions for the bed level change rates. Tests have also demonstrated that models using Engelund & Freds & oslash;e formulae are more sensitive to physical characteristics than models based on Van Rijn, accentuating the necessity to evaluate sediment transport formulae with field data before making a choice of model. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study developed a sediment transport model using MIKE21/3 software to better understand sediment transport in coastal ecosystems. Results showed that both 2D and 3D approaches are useful, with 2D being sufficient for regional scale assessments and 3D allowing for closer examination of influences around tidal farms. Differences in sediment transport rates calculated using different formulas emphasize the need to evaluate sediment transport formulae with field data.