For several years, LAERO and SHOM have developed a high-resolution ocean circulation model based on the non-hydrostatic, non-Boussinesq core of the Coastal and Regional Ocean Community model (CROCO). The simulation uses three two-way nested grids, increasing the resolution from 900 m in the surrounding basins to 60 m over Camarinal Sill, the main topographic feature of the Strait of Gibraltar. This configuration has been extensively validated using data from a field campaign conducted by SHOM aboard R/V L’Atalante in October 2020, dedicated to sampling fine-scale dynamics. The resulting dataset provides valuable insights into small-scale processes (Roustan et al., 2023; 2024a; 2024b). Building on these results, we first assess the model’s ability to reproduce the complex fine-scale structure of the flow and associated mixing. Then, the impact of the nested grid, which enable to simulate the largest turbulent eddies, is further investigated. Finally, preliminary indications of small-scale feedback on the large-scale circulation are discussed.