Experiments in Fluids

, Volume 44, Issue 3, pp 397–408

Dynamic vortex structures for flow-control applications

Authors

    • Institut für Strömungsmechanik, Technische Universität Braunschweig
  • Martin Bitter
    • Institut für Strömungsmechanik, Technische Universität Braunschweig
  • Christian J. Kähler
    • Institut für Strömungsmechanik, Technische Universität Braunschweig
Research Article

DOI: 10.1007/s00348-007-0442-8

Cite this article as:
Ortmanns, J., Bitter, M. & Kähler, C.J. Exp Fluids (2008) 44: 397. doi:10.1007/s00348-007-0442-8

Abstract

It is well known that the application of active flow-control strategies has the potential to increase the efficiency of many devices when compared to static actuator concepts. However, many aspects of the flow-control process are not well understood. In the case of pneumatic vortex generators the importance of coherent structures and their interaction with turbulent boundary layers remains an open question. A flat plate experiment was performed to determine the dynamic evolution of the induced vortex structures using phase-locked stereoscopic Particle Image Velocimetry. The qualification of the actuator system was performed by means of the time-resolved Particle Image Velocimetry measurements of the jet flow. The results show that an initial overshooting of the jet velocity dominates the unsteady start-up process, which results in a vortex structure of larger size and impact. This effect differs essentially from the case of steady blowing. In addition, the ability to shift high-momentum fluid into the near-wall region is a result of strong mixing combined with a minimum distance between the vortex core and the model surface.

Copyright information

© Springer-Verlag 2008