Numerical study of the turbulent eddies generated by the seabed roughness. Case study at a tidal power site

•The lattice Boltzmann method simulates a tidal power flow in large-eddy simulation.•The simulated velocity and velocity variance match in situ measurements.•Large turbulent flow structures are generated over the seabed roughness.•The computational cost is up to 200 times lower than similar existing studies. Strong tidal power flows are highly turbulent. The role of the seabed roughness on the generation of turbulence is not yet fully understood. Numerical simulation is a promising observation method of turbulent events in three dimensions. In this work, the lattice Boltzmann method is used to simulate turbulent tidal flow at a local scale. The capacity of the method to treat large simulation meshes is exploited to attenuate computational costs. Vertical profiles of velocity and velocity variance are generated from the simulation of a 0.23 km2 domain. The simulation is performed with realistic tidal conditions and seabed morphology. Numerical results are in good agreement with in situ acoustic Doppler current profiler measurements. Large turbulent flow structures generated by seabed roughness are observed in the water column through λ2 criterion visualisation.