Control of Compressible Dynamic Stall Using Microjets
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Authors
Shih, C.
Beahn, J.
Krothapalli, A.
Chandrasekhara, M.S.
Subjects
dynamic stall
microjet control
compressible flow
unsteady aerodynamics
separated flow
microjet control
compressible flow
unsteady aerodynamics
separated flow
Advisors
Date of Issue
2003-06
Date
Publisher
Language
Abstract
Control of the dynamic stall process of an NACA 0015
airfoil undergoing periodic pitching motion is investigated
experimentally in a high-speed wind tunnel facility. Multiple
microjet nozzles distributed uniformly in the first 15% chord
from the airfoil’s leading edge are used for the control. Point
Diffraction Interferometry (PDI) technique is used to
characterize the control effectiveness, both qualitatively and
quantitatively. The microjet control has been found to be very
effective in suppressing both the emergence of the dynamic
stall vortex and the associated massive flow separation at the
entire operating range of angles of attack. At the high Mach
number case (M=0.4), the use of microjets appears to eliminate
the shock structures that are responsible for triggering the
shock-induced separation, establishing the fact that the use of
microjets is effective even in controlling dynamic stall with a
strong compressibility effect. In general, microjet jet control
has an overall positive effect in terms of maintaining leading
edge suction pressure and preventing flow separation.
Type
Description
ASME Fluids Engineering Meeting, Honolulu, HI, June 2003.
Series/Report No
Department
Organization
Identifiers
NPS Report Number
Sponsors
Funder
NASA Ames
Format
Citation
C. Shih, J. Beahn, A. Krothapalli and M.S. Chandrasekhara, "Control of Compressible Dynamic Stall Using Microjets", ASME Fluids Engineering Meeting, Honolulu, HI, June 2003.