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Numerical Simulations of Unsteady Low-Reynolds-Number Flows Over the APEX AirfoilLaminar and transitional separation bubbles are an important feature of low-Reynolds-number flows over airfoils. The separation bubbles are unsteady and have a significant impact on the aerodynamic properties of the airfoils. In this paper unsteady low-Reynolds-number separated flows over the APEX airfoil are calculated using a Navier-Stokes solver. The numerical results show the presence of unsteady separation bubbles in the flowfield. An analysis of the numerical results shows that flowfield disturbances are amplified significantly in the separation bubble, leading to periodic vortex shedding. A linear stability analysis of the separated boundary layer is performed and the results show that the dominant wavenumber and frequency in the numerical simulations agree with the most unstable wavenumber and frequency from the linear stability analysis. The numerical results also show the growth and interaction of disturbance waves in the separation bubble. For transonic flows over the APEX airfoil, the calculations show that the presence of shocks causes significant changes in the separation location and consequently, the overall flowfield.
Document ID
19990064492
Acquisition Source
Armstrong Flight Research Center
Document Type
Reprint (Version printed in journal)
Authors
Tatineni, Mahidhar
(California Univ. Los Angeles, CA United States)
Zhong, Xiao-Lin
(California Univ. Los Angeles, CA United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1998
Subject Category
Aerodynamics
Report/Patent Number
AIAA Paper 98-0412
Meeting Information
Meeting: Aerospace Sciences
Location: Reno, NV
Country: United States
Start Date: January 12, 1998
End Date: January 15, 1998
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
CONTRACT_GRANT: NASA Order H-2352
CONTRACT_GRANT: NCC2-374
Distribution Limits
Public
Copyright
Other

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