Finding order to harness chaos: A new approach to understanding and controlling high Reynolds-number wall-bounded turbulence

Project Information

WBT

Grant agreement ID: 277472

Closed project

Start date 1 January 2012

End date 31 December 2017

Funded under

• Specific programme: "Ideas" implementing the Seventh Framework Programme of the European Community for research, technological development and demonstration activities (2007 to 2013)

Total cost € 1 486 500,00

EU contribution € 1 486 500,00

Coordinated by

UNIVERSITY OF SOUTHAMPTON
United Kingdom

Final Report Summary - WBT (Finding order to harness chaos: A new approach to understanding and controlling high Reynolds-number wall-bounded turbulence.)

The enormous impact and significance of high Reynolds-number wall-bounded turbulence in various applications ranging from transportation and energy generation systems to meteorology and oceanography cannot be understated. Therefore, there is a need for new initiatives to predict, model
and control turbulent flows in order to meet current and future challenges. Almost all ideas in modelling and controlling wall-bounded turbulence are based on our limited understanding of low Reynolds-number flows. In higher Reynolds-numbers, we simply assume the existence of mutual
independence of the large-scales located farther away from the wall from the small-scales near the wall. However, this notion of independence is not correct. In fact, these interactions, between large-scales and small-scales play a significant role in various turbulent transport processes in
practical situations. Consequently, our predictive models and control schemes cannot account for or take advantage of these interactions. Therefore, the central question posed in this research project is: What is the physics of scale interactions and how do we take advantage of it?

This project explored the essence of scale interactions and developed new fundamental understanding by performing novel experiments in high Reynolds-number boundary layers. Additionally, unconventional, yet highly innovative experiments were devised to “simulate” essential aspects of
high Reynolds-number wall-bounded turbulence in order to isolate the essence of scale interactions in a controlled environment. State-of-the-art laser diagnostics techniques were developed and employed together with other methods such as hot-wire anemometry and laser anemometry to study the physics of scale interactions. Finally, actuators for the controlling the large-scales in the flow to reduce skin-friction drag were designed and their impact and scalings for high Reynolds flows were discerned.