Spatiotemporal Cooperative Effect Between the Time-asymmetric Ratio of Oscillating Trailing Edge Flap and Pivot Location on the Aerodynamics of a Pitching Airfoil
The time-asymmetric ratio (δ) of an oscillating trailing edge flap (TEF) significantly affects the aerodynamics of a pitching airfoil at low Reynolds numbers and its associated complex flow features. This study aims to investigate how variations in δ influence the lift and drag coefficients for fixe...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Isfahan University of Technology
2025-05-01
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| Series: | Journal of Applied Fluid Mechanics |
| Subjects: | |
| Online Access: | https://www.jafmonline.net/article_2672_da8c727570f86a5281a423d0d3173648.pdf |
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| Summary: | The time-asymmetric ratio (δ) of an oscillating trailing edge flap (TEF) significantly affects the aerodynamics of a pitching airfoil at low Reynolds numbers and its associated complex flow features. This study aims to investigate how variations in δ influence the lift and drag coefficients for fixed-pivot configurations. Numerical simulations indicate that increasing δ enhances lift during the upstroke, and accelerates flow development. This occurs because δ fundamentally modifies the growth rates of various vortices, directly affecting the pressure distribution on the airfoil surface. The study also examines the impact of pivot location (xp/c) on aerodynamic performance and vortex structures at δ = 0. Results reveal that moving the pivot location backward delays flow evolution without improving lift. A detailed assessment of δ and xp/c highlights the spatiotemporal cooperative effect, leading to the proposal of new definitions for the effective angle of attack to these interactions. At a dimensionless number Z = 0.008, setting δ to ±0.1 quantitatively replicates the effect of a forward or backward pivot, shift equivalent to 0.25c. These findings offer valuable insights into the simplified control of airfoil kinematics for achieving exceptional maneuverability and serve a reference for the design of the new flapping machines. |
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| ISSN: | 1735-3572 1735-3645 |