What is it about?
We have developed the new flow control strategy to stably generate vortices using flow control device, such as plasma actuators. 1. Location of flow control device, 2. Length of dominant frequency by flow control, 3. Location of transition point are key parameters for affecting the structual stability of induced vortices. (Please see an attached figure.)
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Why is it important?
The unique point of this flow control strategy is that it uses the degree of turbulence in the region where vortices are developed as an important indicator. The flow control devices such as plasma actuators can generate vortices by intermittent driving, but if the vortex passes through an area of severe turbulence during its development, the vortex is tend to collapse. By contrast, the generated vortices acquire a high degree of structural stability if the vortices are generated within the undisturbed region (laminar boundary layer) by adjusting the location and drive frequency of the flow control device. The generated vortices stably suppress flow separation over the airfoil under the flow conditions for the present study, contributing to the stable improvement in aerodynamic characteristics. In addition, for the flow conditions in the present study (Re=63,000, NACA0015, and so on), the transition point moves further upstream as the magnitude of flow separation increases. The findings suggest the existence of a counterintuitive control mechanism: it is ideal to densely generate smaller vortices as the scale of flow separation increases from the standpoint of control stability and energy consumption.
Perspectives
In recent years, the development of advanced control models using machine learning and deep learning has been active in the research field of flow control. However, we believe that there are important findings that have not yet been raised, even in basic research areas. We hope that the findings of the present study will be useful for the promotion of various studies.
Takuto Ogawa
Tohoku University
Read the Original
This page is a summary of: Revisiting Burst Drive Conditions of DBD Plasma Actuator for Airfoil Flow Control, January 2024, American Institute of Aeronautics and Astronautics (AIAA),
DOI: 10.2514/6.2024-0490.
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