Tidal current energy potential assessment in the Avilés Port using a three-dimensional CFD method

Tidal energy is considered as an energy resource of maximum interest in both technical and research fields due to its largely unexploited energy potential. The use of hydrokinetic microturbines is now an attractive option with reduced environmental impact. The first step to evaluate the feasibility of a hydrokinetic microturbines installation is to perform a study of the velocity field characteristics and therefore the energy potential available. Up to now, different numerical models, of one, two and three spatial dimensions have been applied to evaluate the tidal potential in large areas. Due to the high computational resources needed, they include simplifications, like avoiding a precise study of the velocity in the vertical dimension, resulting in incomplete estimations of the available kinetic energy. To complete these estimations, the research presented sets out a methodology to evaluate the current effects, velocity profiles and the energy potential derived from tide movements in an estuary or port by solving the full Navier–Stokes equations. It also considers the water–air interface in the numerical scheme. The methodology is based, firstly, on the definition of a three-dimensional geometrical model of the geographical area of study, and then, the complete model is meshed with finite volumes, where the full three-dimensional Unsteady Navier–Stokes equations are solved. The methodology was applied and validated with a three-dimensional water–air numerical model of the port of Aviles (Spain). In conclusion, water surface elevations, averaged speed cycles, velocity profiles as a function of depth and tidal power and energy data have been obtained without the usual simplifications, which will mean an evaluation more accurate when assessing the implementation of a power generation system.