Flow field characterization of a jet and vortex actuator |
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Authors: | J T Lachowicz C Yao R W Wlezien |
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Institution: | (1) NASA Langley Research Center, Hampton, VA 23681, USA, US |
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Abstract: | An actuator, which produces several different flow fields that may be used for active flow control, is characterized in still
air using flow visualization and velocity measurements. The primary actuator-induced flow fields are: free jets, wall jets,
and vortex flows. The non-dimensional parameters governing these actuator-induced flows are developed. For the vortex-flow
regime, the operational range of the actuator increases as it’s size decreases without a significant decrease in either the
actuator induced velocity or vortex core size. The velocity scaling is developed for the vortex flow and suggests that the
optimum actuator efficiency occurs at a Stokes number of approximately 7.9 for the range of parameters surveyed. In a turbulent,
zero pressure gradient boundary layer, measurements made just downstream of the actuator (when operated in the vortex mode)
indicate a vortical disturbance is generated in the boundary layer.
Received: 2 September 1998/Accepted: 9 January 1999 |
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