TY - GEN
T1 - Effect of reduced frequency on dynamic stall of a pitching airfoil in a turbulent wake
AU - Gandhi, Anurag
AU - Merrill, Brandon
AU - Peet, Yulia
N1 - Funding Information:
We would like to acknowledge support for this work given by the National Science Foundation grant CMMI-1250124. Computational support by the NSF XSEDE program through the computational resource allocation on the SDSC Comet cluster as well as by Arizona State University on the Pitchfork and Sparky clusters is gratefully acknowledged as well.
Publisher Copyright:
© 2017 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
PY - 2017
Y1 - 2017
N2 - In this paper, we investigate the influence of an airfoil pitching frequency (reduced frequency) on dynamic stall behavior of a NACA0012 airfoil oscillating in a turbulent wake with Direct Numerical Simulations. The presence of an upstream turbulence with dynamically oscillated blades and airfoils is associated with the ambient flow unsteadiness and is encountered in many operating conditions. We have recently developed a methodology that allows us to study the effects of wake turbulence on an oscillating airfoil with high-fidelity moving overlapping grid approach in high-order numerical formulation. The turbulent wake is generated by a small solid cylinder placed upstream of an oscillating airfoil, and the vortices shed from the upstream cylinder interfere with the pitching airfoil dynamics that alters the dynamic stall characteristics. In this paper, we study how the effects of the wake turbulence on the dynamic stall change when the reduced frequency is changed. We compare two reduced frequencies for the airfoil oscillation, k = 0:16 and 0:25, and document the corresponding flow-fields and aerodynamic coefficients. We focus on understanding how the vortex dynamics change in different cases and how it effects the airfoil aerodynamic characteristics.
AB - In this paper, we investigate the influence of an airfoil pitching frequency (reduced frequency) on dynamic stall behavior of a NACA0012 airfoil oscillating in a turbulent wake with Direct Numerical Simulations. The presence of an upstream turbulence with dynamically oscillated blades and airfoils is associated with the ambient flow unsteadiness and is encountered in many operating conditions. We have recently developed a methodology that allows us to study the effects of wake turbulence on an oscillating airfoil with high-fidelity moving overlapping grid approach in high-order numerical formulation. The turbulent wake is generated by a small solid cylinder placed upstream of an oscillating airfoil, and the vortices shed from the upstream cylinder interfere with the pitching airfoil dynamics that alters the dynamic stall characteristics. In this paper, we study how the effects of the wake turbulence on the dynamic stall change when the reduced frequency is changed. We compare two reduced frequencies for the airfoil oscillation, k = 0:16 and 0:25, and document the corresponding flow-fields and aerodynamic coefficients. We focus on understanding how the vortex dynamics change in different cases and how it effects the airfoil aerodynamic characteristics.
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U2 - 10.2514/6.2017-0720
DO - 10.2514/6.2017-0720
M3 - Conference contribution
AN - SCOPUS:85017195493
T3 - AIAA SciTech Forum - 55th AIAA Aerospace Sciences Meeting
BT - AIAA SciTech Forum - 55th AIAA Aerospace Sciences Meeting
PB - American Institute of Aeronautics and Astronautics Inc.
T2 - 55th AIAA Aerospace Sciences Meeting
Y2 - 9 January 2017 through 13 January 2017
ER -