Interaction of marine turbines in close proximity

This paper describes the results of a CFD assessment of a small array of turbines. The primary objective was to determine how the separation between turbines affects the output from the individual, and hence collective, turbines. The turbines considered have been scaled from a validated laboratory turbine, using non-dimensionalised terms. The results of this work identify that the separation between the turbines can be reduced to approximately two turbine diameters, where the flow accelerates between the turbines. This increased velocity results in a small increase in the power output. Counter rotating turbines in a row were also shown to improve the performance. The rotational flow between the turbines is in the same direction thus reducing the shear rate. In addition, the lateral position of a second row of turbines can be as critical to the power output as the downstream distance from the first row. Turbines, however, positioned directly behind the first row of turbines, at the same longitudinal position, show a reduction in the velocity and an increased level of turbulence, hence reduced power output.