Work

Spatiotemporal Cooperative Effect Between the Time-asymmetric Ratio of Oscillating Trailing Edge Flap and Pivot Location on the Aerodynamics of a Pitching Airfoil

Year: 2025

Type: article

Abstract: 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.

Source: Journal of Applied Fluid Mechanics

DOI: 10.47176/jafm.18.7.3237

Authors: L. Zhu, R. Guo, Z. Lai, L. Qi, C. Yin

Institutions: Guizhou University, Zhejiang Lab

Language: English

Topic: Biomimetic flight and propulsion mechanisms

Subfield: Aerospace Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: diamond

Funders: National Natural Science Foundation of China, Guizhou University

Award: G3090562001