Transonic Testing of passive flow control techniques in the Pilot European Transonic Cryogenic Wind Tunnel

Lead Research Organisation: Cranfield University
Department Name: Sch of Aerospace, Transport & Manufact


The reduction of aircraft fuel burn, which results in reduced carbon emissions, is of vital importance to aviation and society in general. One way to do this is to reduce the aircraft drag - the air resistance to its flight. This is particularly true if aircraft are to operate at lower altitude where CO2 emissions do less harm, but where air density is higher. One way to do this is to employ passive (requiring no energy input) methods to control the airflow to ensure that the wing shock waves are weakened and do not cause the flow to diverge from the wing and become turbulent (separation). A consortia of UK Universities and representatives from industry (Airbus, BAe Systems, DSTL and the Aerospace Technology Institute) will undertake a campaign of fundamental experiments at the cryogenic European Transonic Wind Tunnel in Cologne, to investigate whether strips of small scale roughness on a small scale, but representative wing section, can effectively act to weaken the wing shock wave.


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Description 1) This project, funded by Airbus UK, the European Transonic Wind Tunnel and EPSRC resulted in the discovery that the shock bump effect, whereby the detrimental effects of transonic shock waves on aircraft wings can be reduced by the addition of periodic surface bumps under the shock wave, can be achieved using strips of distributed sand paper like roughness. This virtual shock bump effect is less intrusive, does not require the re-design of a wing and therefore can be employed as a retrofit to current operational aircraft as well as new aircraft, to improve flight efficiency and improve safety.

2) This project enabled the UK academic community, through the National Wind Tunnel Facility, to engage in this project and share in the learning and experience of cryogenic wind tunnel testing, which is not available in the UK itself. This has enabled a significant boost in the level of experience in this modern and vital area of wind tunnel testing within the UK community, allowing better informed teaching and new collaboration opportunities for UK academia.
Exploitation Route There is now an intention that the National Wind Tunnel Facility will work with Airbus / ETW and DSTL to work on a series of collaborative experimental research projects in the ETW facilities to improve the quality and impact of UK research in transonic aerodynamics, and foster better international collaborations.
Sectors Aerospace, Defence and Marine,Education,Environment,Transport

Description The project has enabled closer links between UK academia and European partner institutions, particularly in Germany.
First Year Of Impact 2022
Sector Aerospace, Defence and Marine,Education,Environment,Security and Diplomacy,Transport
Impact Types Cultural,Economic

Description Continued collaboration between Cranfield, NWTF and ETW 
Organisation European Transonic Windtunnel
Country Germany 
Sector Private 
PI Contribution Contributing knowledge of aerodynamic flow control, and a specific novel method.
Collaborator Contribution Testing time in a cryogenic wind tunnel to aqcuire experimental data.
Impact Reports and journal papers planned.
Start Year 2020