Wind farm characteristics of side-by-side and tandem configurations

Abstract

This study explores the effects of different arrangements such as side-by-side and tandem in wind turbine towers under various Reynolds numbers. The Reynolds number was changed from 1.2x10(3) to 4x10(6). The wake flow behaviors, velocity characteristics, and wake vortex shedding were studied. The effects of side-by-side gap ratio (G*) and tandem gap ratio (L*) were considered. Smoke-wire flow visualization technique was used to render the flow characteristics. At different heights, the flow characteristics were observed in four sections: the blade at tower top, bluff body of blade and generator, cylinder of wind turbine tower, and junction at the bottom. A hot-wire anemometer was used to measure the vortex-street frequency. The characteristic flow modes for the side-by-side configuration are the anti- and in-phase vortex modes, and those for the tandem arrangement are the single, attached, and bi-vortex modes. For side-by-side wind towers, the wake flow field behaved like that of single one when G* > 1.0. For tandem wind turbine towers, the flow behaviors are independent when L* > 0.85.