Near Wake Dynamics of a Cross-Flow Turbine Array

TL;DR

This study investigates how the wake dynamics and efficiency of a two-cross-flow turbine array are affected by rotation direction and phase difference, providing insights into turbine interactions in array configurations.

Contribution

It offers new experimental data on wake behavior and efficiency variations in a cross-flow turbine array under different rotational and phase conditions.

Findings

Efficiency depends on rotation direction and phase difference.

Wake flow fields vary with turbine rotation configurations.

Interactions between turbines influence overall performance.

Abstract

Cross-flow turbines, also known as vertical-axis turbines, convert the kinetic energy in moving fluid to mechanical energy using blades that rotate about an axis perpendicular to the incoming flow. In these experiments, the performance and wake of a two-turbine array in a fence configuration (side-by-side) was characterized. The turbines were operated under coordinated control, a strategy characterized by synchronous rotation rates with a mean phase difference. Measurements were made with turbines co-rotating, counter-rotating with the blades advancing upstream at the array midline, and counter-rotating with the blades retreating downstream at the array midline. From the performance data, we find individual turbine and array efficiency depend significantly on rotation direction and phase difference. Variations are also observed in the wake flow field and, using these data, we hypothesize how rotation direction and phase influence interactions between adjacent turbines.