ISSN Online: 2688-7231
ISBN Online: 978-1-56700-524-0
Proceedings of the 26thNational and 4th International ISHMT-ASTFE Heat and Mass Transfer Conference December 17-20, 2021, IIT Madras, Chennai-600036, Tamil Nadu, India
Comparison of wake characteristics behind a custom designed airfoil performing different types of flapping oscillations
Аннотация
The present study investigates the wake dynamics behind a
custom designed airfoil undergoing different types of flapping
oscillations. The two-dimensional laminar incompressible
flow past the flapping airfoil performing the pitching motion,
heaving motion and combined pitch-heave motion is studied
numerically using OpenFOAM. The influence of flapping
parameters are investigated for a range of Strouhal number
based on amplitude, StA varying from 0.1 ≤ StA ≤ 0.4 at a constant Reynolds number, Re=2640. A comparison of the wake structure behind the airfoil for three different types of flapping motion is presented. The generation of vorticity above and below the airfoil depends on the initial direction of motion of the airfoil and remains same for all types of flapping motion investigated. The flapping parameters appear to influence the evolution of leading edge and trailing edge vortices. The pitching motion governs the dynamics of the combined pitch-heave motion at lower values of StA (StA < 0.24) while the heaving motion governs the dynamics at
higher values of StA (StA>0.24). The force computations reveal that the formation of reverse von Karman Street is not adequate to develop thrust on the airfoil.