EUDP Project: Low Noise Airfoil - Final Report

Research output: Book/ReportReportResearch

400 Downloads (Pure)

Abstract

This document summarizes the scientific results achieved during the EUDP-funded project `Low-Noise Airfoil'. The goals of this project are, on one side to develop a measurement technique that
permits the evaluation of trailing edge noise in a classical aerodynamic wind tunnel, and on the other side to develop and implement a design procedure to manufacture airfoil profiles with low noise emission. The project involved two experimental campaigns: one in the LM Wind Power wind tunnel, a classical aerodynamic wind tunnel, in Lunderskov (DK), the second one in the Virginia Tech Stability Wind Tunnel at the Aerospace and Ocean Engineering Department of Virginia Tech (Blacksburg, VA,(USA), also a classical aerodynamic wind tunnel but equipped with an anechoic chamber that allow to perform acoustic measurements. On the theoretical side, the above experiments yield a series of model validations and improvements. In particular, the so-called TNO trailing edge noise model could be significantly improved by introducing turbulence anisotropy in its formulation, as well as the influence of the boundary layer mean pressure gradient. This two characteristics are inherent to airfoil flows but were neglected in the original approach. In addition, the experimental results are confronted to detailed Large Eddy Simulations of the airfoil flow giving more insight into the flow turbulence characteristics. The methodology which consists in measuring surface pressure spectra directly on the airfoil surface using flush-mounted microphones in order to evaluate far-field noise emission using additional theoretical results has been validated. This technique presents the advantage that it can easily be used in a classical aerodynamic wind tunnel and does not require the use of an anechoic facility. It was developed as a substitute to the original plan that consisted in measuring acoustic waves using hot-wire velocimetry. This last technique proved ineffective in the LM Wind Tunnel as the high
ambient noise levels largely overwhelmed the signal of interest. Finally, a new airfoil design was proposed based on a design concept including noise reduction. The new airfoil proved to perform better aerodynamically but noise reduction were not as important as expected, mainly due to the inaccuracy of the simplified flow model used in the design algorithm.
Original languageEnglish
PublisherWind Energy Department, Technical University of Denmark
Number of pages64
ISBN (Electronic)978-87-92896-03-2
Publication statusPublished - 2012
SeriesDTU Wind Energy E
Number0004

Keywords

  • DTU-Wind-Energy-E-0004(EN)
  • DTU-Wind-Energy-Report-E-0004

Cite this

Bertagnolio, F. (Ed.) (2012). EUDP Project: Low Noise Airfoil - Final Report. Wind Energy Department, Technical University of Denmark. DTU Wind Energy E, No. 0004
Bertagnolio, Franck (Editor). / EUDP Project: Low Noise Airfoil - Final Report. Wind Energy Department, Technical University of Denmark, 2012. 64 p. (DTU Wind Energy E; No. 0004).
@book{f9d8f0c574a4485ca9c3deb1fea661ac,
title = "EUDP Project: Low Noise Airfoil - Final Report",
abstract = "This document summarizes the scientific results achieved during the EUDP-funded project `Low-Noise Airfoil'. The goals of this project are, on one side to develop a measurement technique that permits the evaluation of trailing edge noise in a classical aerodynamic wind tunnel, and on the other side to develop and implement a design procedure to manufacture airfoil profiles with low noise emission. The project involved two experimental campaigns: one in the LM Wind Power wind tunnel, a classical aerodynamic wind tunnel, in Lunderskov (DK), the second one in the Virginia Tech Stability Wind Tunnel at the Aerospace and Ocean Engineering Department of Virginia Tech (Blacksburg, VA,(USA), also a classical aerodynamic wind tunnel but equipped with an anechoic chamber that allow to perform acoustic measurements. On the theoretical side, the above experiments yield a series of model validations and improvements. In particular, the so-called TNO trailing edge noise model could be significantly improved by introducing turbulence anisotropy in its formulation, as well as the influence of the boundary layer mean pressure gradient. This two characteristics are inherent to airfoil flows but were neglected in the original approach. In addition, the experimental results are confronted to detailed Large Eddy Simulations of the airfoil flow giving more insight into the flow turbulence characteristics. The methodology which consists in measuring surface pressure spectra directly on the airfoil surface using flush-mounted microphones in order to evaluate far-field noise emission using additional theoretical results has been validated. This technique presents the advantage that it can easily be used in a classical aerodynamic wind tunnel and does not require the use of an anechoic facility. It was developed as a substitute to the original plan that consisted in measuring acoustic waves using hot-wire velocimetry. This last technique proved ineffective in the LM Wind Tunnel as the high ambient noise levels largely overwhelmed the signal of interest. Finally, a new airfoil design was proposed based on a design concept including noise reduction. The new airfoil proved to perform better aerodynamically but noise reduction were not as important as expected, mainly due to the inaccuracy of the simplified flow model used in the design algorithm.",
keywords = "DTU-Wind-Energy-E-0004(EN), DTU-Wind-Energy-Report-E-0004",
editor = "Franck Bertagnolio",
year = "2012",
language = "English",
series = "DTU Wind Energy E",
number = "0004",
publisher = "Wind Energy Department, Technical University of Denmark",

}

Bertagnolio, F (ed.) 2012, EUDP Project: Low Noise Airfoil - Final Report. DTU Wind Energy E, no. 0004, Wind Energy Department, Technical University of Denmark.

EUDP Project: Low Noise Airfoil - Final Report. / Bertagnolio, Franck (Editor).

Wind Energy Department, Technical University of Denmark, 2012. 64 p. (DTU Wind Energy E; No. 0004).

Research output: Book/ReportReportResearch

TY - RPRT

T1 - EUDP Project: Low Noise Airfoil - Final Report

A2 - Bertagnolio, Franck

PY - 2012

Y1 - 2012

N2 - This document summarizes the scientific results achieved during the EUDP-funded project `Low-Noise Airfoil'. The goals of this project are, on one side to develop a measurement technique that permits the evaluation of trailing edge noise in a classical aerodynamic wind tunnel, and on the other side to develop and implement a design procedure to manufacture airfoil profiles with low noise emission. The project involved two experimental campaigns: one in the LM Wind Power wind tunnel, a classical aerodynamic wind tunnel, in Lunderskov (DK), the second one in the Virginia Tech Stability Wind Tunnel at the Aerospace and Ocean Engineering Department of Virginia Tech (Blacksburg, VA,(USA), also a classical aerodynamic wind tunnel but equipped with an anechoic chamber that allow to perform acoustic measurements. On the theoretical side, the above experiments yield a series of model validations and improvements. In particular, the so-called TNO trailing edge noise model could be significantly improved by introducing turbulence anisotropy in its formulation, as well as the influence of the boundary layer mean pressure gradient. This two characteristics are inherent to airfoil flows but were neglected in the original approach. In addition, the experimental results are confronted to detailed Large Eddy Simulations of the airfoil flow giving more insight into the flow turbulence characteristics. The methodology which consists in measuring surface pressure spectra directly on the airfoil surface using flush-mounted microphones in order to evaluate far-field noise emission using additional theoretical results has been validated. This technique presents the advantage that it can easily be used in a classical aerodynamic wind tunnel and does not require the use of an anechoic facility. It was developed as a substitute to the original plan that consisted in measuring acoustic waves using hot-wire velocimetry. This last technique proved ineffective in the LM Wind Tunnel as the high ambient noise levels largely overwhelmed the signal of interest. Finally, a new airfoil design was proposed based on a design concept including noise reduction. The new airfoil proved to perform better aerodynamically but noise reduction were not as important as expected, mainly due to the inaccuracy of the simplified flow model used in the design algorithm.

AB - This document summarizes the scientific results achieved during the EUDP-funded project `Low-Noise Airfoil'. The goals of this project are, on one side to develop a measurement technique that permits the evaluation of trailing edge noise in a classical aerodynamic wind tunnel, and on the other side to develop and implement a design procedure to manufacture airfoil profiles with low noise emission. The project involved two experimental campaigns: one in the LM Wind Power wind tunnel, a classical aerodynamic wind tunnel, in Lunderskov (DK), the second one in the Virginia Tech Stability Wind Tunnel at the Aerospace and Ocean Engineering Department of Virginia Tech (Blacksburg, VA,(USA), also a classical aerodynamic wind tunnel but equipped with an anechoic chamber that allow to perform acoustic measurements. On the theoretical side, the above experiments yield a series of model validations and improvements. In particular, the so-called TNO trailing edge noise model could be significantly improved by introducing turbulence anisotropy in its formulation, as well as the influence of the boundary layer mean pressure gradient. This two characteristics are inherent to airfoil flows but were neglected in the original approach. In addition, the experimental results are confronted to detailed Large Eddy Simulations of the airfoil flow giving more insight into the flow turbulence characteristics. The methodology which consists in measuring surface pressure spectra directly on the airfoil surface using flush-mounted microphones in order to evaluate far-field noise emission using additional theoretical results has been validated. This technique presents the advantage that it can easily be used in a classical aerodynamic wind tunnel and does not require the use of an anechoic facility. It was developed as a substitute to the original plan that consisted in measuring acoustic waves using hot-wire velocimetry. This last technique proved ineffective in the LM Wind Tunnel as the high ambient noise levels largely overwhelmed the signal of interest. Finally, a new airfoil design was proposed based on a design concept including noise reduction. The new airfoil proved to perform better aerodynamically but noise reduction were not as important as expected, mainly due to the inaccuracy of the simplified flow model used in the design algorithm.

KW - DTU-Wind-Energy-E-0004(EN)

KW - DTU-Wind-Energy-Report-E-0004

M3 - Report

T3 - DTU Wind Energy E

BT - EUDP Project: Low Noise Airfoil - Final Report

PB - Wind Energy Department, Technical University of Denmark

ER -

Bertagnolio F, (ed.). EUDP Project: Low Noise Airfoil - Final Report. Wind Energy Department, Technical University of Denmark, 2012. 64 p. (DTU Wind Energy E; No. 0004).