Operational-dependent wind turbine wake impact on surface momentum flux revealed by snow-powered flow imaging

TL;DR

This study visualizes wind turbine wake interactions with the ground using snow-powered flow imaging, revealing operational-dependent pathways that influence surface momentum flux and impact wind farm siting and agriculture.

Contribution

It introduces a novel snow-powered imaging method to analyze turbine wake effects and identifies operational pathways affecting surface fluxes, resolving previous conflicting findings.

Findings

Intermittent strong wake-ground interactions observed

Two operational pathways influence momentum flux

Generated a US-wide impact map for wind farm siting

Abstract

As wind energy continues to expand, increased interaction between wind farms and their surroundings can be expected. Using natural snowfall to visualize the air flow in the wake of a utility-scale wind turbine at unprecedented spatio-temporal resolution, we observe intermittent periods of strong interaction between the wake and the ground surface and quantify the momentum flux during these periods. Significantly, we identify two turbine operational-dependent pathways that lead to these periods of increased wake-ground interaction. Data from a nearby meteorological tower provides further insights into the strength and persistence of the enhanced flux for each pathway under different atmospheric conditions. These pathways allow us to resolve discrepancies between previous conflicting studies on the impact of wind turbines on surface fluxes. Furthermore, we use our results to generate a map of the potential impact of wind farms on surface momentum flux throughout the Continental United States, providing a valuable resource for wind farm siting decisions. These findings have implications for agriculture in particular, as crop growth is significantly affected by surface fluxes.