Analysis of a plane turbulent mixing layer manipulated by a localized forced separation

Abstract

The purpose of this experimental study is to analyze the effects of a forced separation, near the trailing edge of a splitter plate, on the development of a turbulent plane mixing layer. The separation was driven by a steady pneumatic injection, and is considered here as an actuator for controlling the spreading efficiency of the mixing layer. Particle image velocimetry and hot-wire measurements were performed for the natural and the manipulated regimes. The results highlight the capabilities of this control strategy to enhance mixing. Analysis of the turbulent field and coherent structure organization offers insight into the mechanisms responsible for this mixing enhancement.

Keywords:

• Flow control
• Forced separation
• Turbulent plane mixing layer

Acknowledgments

Support of this work was provided by the CNRS, Region Poitou-Charentes and the French Ministry of Research through the COS program. The authors also thank Carine Fourment and Patrick Braud for their assistance in measurements.