Passive and Active Flow-Control in the Turbulent Three-Dimensional Wall Jet

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It is generally accepted that organized turbulent motions persist beneath seemingly random turbulent flows. These organized motions, or coherent structures are linked to many properties of engineering interest, like drag, heat-transfer or noise production. The present research program is aimed at improving our understanding of how to control these coherent structures by both passive and active means to produce useful engineering results like drag-reduction, enhanced heat-transfer, and reduced noise emissions. Flow-control techniques like these have the potential to save billions of dollars in annual fuel savings and produce more economical and environmentally friendly industrial processes. The objective of the proposed research is to experimentally control the coherent structures in a three-dimensional wall jet by both active and passive means to reduce and enhance the lateral development of the flow. Both outcomes are useful in many practical applications. In particular, enhancing surface coverage of the jet is advantageous where large areas heat-transfer are required, whereas, reducing the lateral development of the jet will likely enhance mixing and be useful in combustion applications. Using our existing knowledge of the organized turbulent motions in the jet, the first phase of the research will employ passive control techniques (like vortex generators) to control the lateral development of the jet. The second phase of the research is aimed at working towards advanced reactive flow control capabilities and will improve our flow sensing capabilities using multi-point wall pressure measurements.