TY - GEN
T1 - Unsteady Evolution of a Laminar Separation Bubble Subjected to Structural Motion
AU - Guerra, Adrián Grille
AU - Hosseinverdi, Shirzad
AU - Sing, Ashish
AU - Little, Jesse
AU - Fasel, Hermann
N1 - Funding Information:
This work was supported by the Air Force Office of Scientific Research (AFOSR) under grant number FA9550-19-1-0174 with Dr. Gregg Abate serving as the program manager. Computer time for numerical simulations was provided by the University of Arizona High Performance Computing center.
Publisher Copyright:
© 2021, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
PY - 2021
Y1 - 2021
N2 - Experiments and direct numerical simulations are employed to investigate the laminar separation bubble that forms on the suction side of a static and plunging wing section for a modified NACA 643 - 618 airfoil at a chord Reynolds number of Re = 200k. The simulations show that the transition process in the separated shear layer is mainly due to the amplification of Kelvin-Helmholtz instabilities, followed by shedding of strong spanwise coherent structures that lead to the reattachment of a turbulent boundary layer. A plunging motion with an amplitude of h = 6% of the chord and a reduced frequency of k = 0.67 is imposed to the wing in a wind tunnel experiment, at a nominal angle of attack of zero degrees. Surface pressure and 2D Particle Image Velocimetry measurements are used to track the unsteady evolution of the bubble along the plunging cycle and its effect on the wing’s loading. A hysteretic behaviour is observed for the bubble size and location during the cycle. No bubble bursting is observed at these conditions, thus having a small impact on the global lift and pitching moment coefficientsof the wing.
AB - Experiments and direct numerical simulations are employed to investigate the laminar separation bubble that forms on the suction side of a static and plunging wing section for a modified NACA 643 - 618 airfoil at a chord Reynolds number of Re = 200k. The simulations show that the transition process in the separated shear layer is mainly due to the amplification of Kelvin-Helmholtz instabilities, followed by shedding of strong spanwise coherent structures that lead to the reattachment of a turbulent boundary layer. A plunging motion with an amplitude of h = 6% of the chord and a reduced frequency of k = 0.67 is imposed to the wing in a wind tunnel experiment, at a nominal angle of attack of zero degrees. Surface pressure and 2D Particle Image Velocimetry measurements are used to track the unsteady evolution of the bubble along the plunging cycle and its effect on the wing’s loading. A hysteretic behaviour is observed for the bubble size and location during the cycle. No bubble bursting is observed at these conditions, thus having a small impact on the global lift and pitching moment coefficientsof the wing.
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U2 - 10.2514/6.2021-2949
DO - 10.2514/6.2021-2949
M3 - Conference contribution
AN - SCOPUS:85123899724
SN - 9781624106101
T3 - AIAA Aviation and Aeronautics Forum and Exposition, AIAA AVIATION Forum 2021
BT - AIAA Aviation and Aeronautics Forum and Exposition, AIAA AVIATION Forum 2021
PB - American Institute of Aeronautics and Astronautics Inc, AIAA
T2 - AIAA Aviation and Aeronautics Forum and Exposition, AIAA AVIATION Forum 2021
Y2 - 2 August 2021 through 6 August 2021
ER -