Presentations

Abstract

In this paper, we investigate the impact of a novel flexible serrated trailing edge device on the reduction of far-field broadband noise through reductions in sound energy in the low- to mid-frequency spectrum (< 1000 Hz) on a modern 6-MW class wind turbine. Immission point measurements at 700 m were carried out during consecutive years in the same season with the only change being the serration type on the turbine, starting first with a current saw-tooth serration (baseline period), and moving to a novel flexible serration (altered period). This technology is designed to target frequencies below 2 kHz, and especially in the range of 200-800 Hz. While IEC 61400-12-2:2024 (ed. 3) measurements demonstrated a delta SPL reduction of around 2dBA at 250m, measurements at the immission point at 700m showed reductions of 3.5 - 4 dBA. This increase in delta reduction is explained by the average reductions seen in the low frequency spectrum. Standard propagation modelling utilizing ISO 9613-2 standards gives further insights, especially when looking at the 1/3 frequency band distribution at 250m and 700m. An investigation into best practices within the framework of the current industry methodology follows.