Author(s): Nandhini Duraimurugan; Holger Schuttrumpf; Harish Selvam And Murali Kantharaj

Linked Author(s): Nandhini Duraimurugan

Keywords: Spur dikes; Tidal bore; Numerical simulation; Blockage ratio; Wall effect

Abstract: In river engineering, spur dikes can be used for various purposes like directing flow or protecting the river banks and beaches. A series of spur dikes hold the flow within a narrow channel, thereby protecting the erodible banks. In the past, different spur dikes were examined by varying their orientation, spacing and dimensions to study the variations in hydrodynamics, sediment transport and scouring under regular river flow conditions. These experiments were conducted for a particular obstruction ratio in the experimental flume. However, there is a lacuna in the literature on the maximum length of the structure that can be tested in the laboratory without a wall effect. This study aims to understand the optimum blockage ratio (BR) for the caisson-type spur dike configuration that can be modelled in the laboratory, especially for tidal bore interaction with a series of spurs. Herein, BR is the ratio of the spur dike length (L) and the channel width (W). In this study, the BR value varied between 0.1 and 0.7. The numerical simulation was carried out using the open-source CFD solver OpenFOAM in which the dam-break surge was used to replicate the tidal bore. The blockage effect was identified by the variation in the flow depth characteristics due to the presence of spur dikes by comparing it with the no-spur dike configuration. The study outcomes are expected to identify the optimum BR limits to avoid the flume side wall effects in laboratory experiments for extreme flow structure interactions.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P2139-cd

Year: 2025