SURFACE TREATMENTS FOR NEXT GENERATION OF QUIET AEROFOILS

Lead Research Organisation: University of Southampton
Department Name: Sch of Engineering

Abstract

A major advance in the reduction of aerofoil trailing edge self-noise has recently been made by the team at Virginia Tech led by Professors William Devenport and Stewart Glegg, collaborators in this project. They demonstrated that introducing 'canopies' into the turbulent boundary layer, which may be constructed from fabric, wires, or rods, produced significant reductions in the surface pressure spectrum near the trailing edge, and hence similar reductions in the far field noise. These treatments were chosen to reproduce the downy canopy that covers the surface of exposed flight feathers of many owl species. Aerofoil self-noise is often the dominant noise source emitted from lifting surfaces, such as aerofoils and turbine blades, and is a major issue in a number of strategically important sectors in the UK, including environment, energy and transport. This work is in its early stages and the precise control mechanisms are poorly understood.

This 36-month project is concerned with establishing the fundamental physical control mechanisms of surface treatments with the objective of developing effective treatments on aerofoil geometries at realistic Reynolds numbers and Angle of attack (AoA) that do not significantly degrade aerodynamic performance. The project is a combination of advanced and detailed experimentation together with the application of recent advances in high-resolution computational methods and high-performance computing. At the heart of this project is the use of a new turbulent off-wall boundary condition to allow accurate modelling of the interaction between the boundary layer and canopy surfaces.
 
Description 1. The use of thin rods located just above the trailing edge of an aerofoil can greatly reduce its trailing edge broadband noise. The study has shown that thinner rods are effective due to higher rates of turbulence energy dissipation over the rods.

2. A new method for predicting the surface pressure beneath a spanwise varying boundary layer has been developed, providing insight into the precise mechanism of pressure fluctuations on an aerofoil surface.
Exploitation Route The technology could be of use to wind turbine manufactures, although the exact impact on aerodynamic performance remains to be determined.
Sectors Aerospace

Defence and Marine

Energy

Environment

Transport

 
Description SURFACE TREATMENTS FOR NEXT GENERATION QUIET AEROFOILS
Amount £1,200,000 (GBP)
Funding ID X313200X 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 07/2021 
End 08/2024
 
Title A widely used method for calculating the surface pressure spectrum over an aerofoil using information about the boundary layer has been extended to include spanwise variations in flow. This generalisation also provides insight into the physics of surface pressure fluctuations benerath boundary layers. 
Description the widely used 'TNO' model by which the surface pressure spectrum beneath a turbulent boundary layer has been extended to include spanwise variations in flow. This non-trivial extension greatly extends the use of this method. 
Type Of Material Improvements to research infrastructure 
Year Produced 2022 
Provided To Others? Yes  
Impact Not yet 
 
Description Collaboration with Dr Thomas Geyer at Cotbus University in Germany on the use of porous materials for noise reduction 
Organisation Deutsches Zentrum für Musiktherapieforschung
Country Germany 
Sector Public 
PI Contribution One of the partners of the project, Dr Philip Woodhead, has spent at the University of Cotbus in Germany working on a new low-noise aerofoil
Collaborator Contribution Philip Has aquired new data in the wind tunnel facility at Cotbus, which is currenly being analysed.
Impact Data is currently being analysed
Start Year 2021
 
Description Collaboration with scientists at Cambridge University 
Organisation University of Cambridge
Department Department of Applied Mathematics and Theoretical Physics (DAMTP)
Country United Kingdom 
Sector Academic/University 
PI Contribution Provision of experimental data.
Collaborator Contribution Regular meetings with academics from Cambridge applied maths dept whose work compliments our own
Impact conference papers
Start Year 2021
 
Description Collaboration with scientists at TU Delft 
Organisation Delft University of Technology (TU Delft)
Country Netherlands 
Sector Academic/University 
PI Contribution Transfer of idea to TU Delft to start collaboration
Collaborator Contribution Our post-doc is working for 2 weeks in TU Delft for us to learn of their experimental methods.
Impact None yet
Start Year 2021
 
Description School visit, university open days 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Results from this project were central to presentations given to a general audience and school children on methods for reducing aerofoil and propeller noise based on ideas taken from nature.
Year(s) Of Engagement Activity 2021