A Numerical Simulation on the Airfoil S833 Equipped with Flapping Trailing Edge Fringes

Abstract

Design optimization has been increasingly investigated for an airfoil, aiming to reduce the vorticity in the wake and increase the aerodynamic performance. In the current work, a two-dimensional (2D) S833 airfoil equipped with a flapping fringe at the trailing edge has been studied using computational fluid dynamics (CFD) simulations. The objective is to investigate the influence of the length (Lf) and flapping frequency (f) of the fringe on shedding vortices from the airfoil and the drag and lift coefficients. The validation of the current numerical approach for both static and dynamic motions of the airfoil was conducted. First, four different computational meshes were created for the static bare airfoil S833 model, and the simulated drag and lift coefficients were compared against experimental results. It is observed that the second finest mesh contributes to the best agreement with the measurement data. In addition, the numerical accuracy of the dynamic simulation was assessed by reproducing the pressure distribution around the airfoil NACA0014 with a periodic plunging motion at different time phases within one plunging cycle. Good agreements between the simulated and previous computational results are obtained. Moreover, the investigation of S833 airfoil equipped with a flapping fringe reveals that the model with Lf =0.01 m (10% of the chord length) associated with a flapping frequency below the shedding frequency of the bare airfoil can significantly alter the coherent structure of the shedding vortices, breaking the routine large-scale vortex into small-scale weak vortices. It also results in reducing the intensity of vortices and shortening the distance between each pair of vortices to accelerate the dissipation of vorticity. In addition, the equipped flapping trailing edge fringe can achieve extra benefit in aerodynamic performance in terms of the reduction of the drag coefficients and the enhancement of lift coefficients.

A parametric study of the effect of self-oscillating trailing-edge flaplets on aerofoil self-noise

“…In total, all the flaplets effectively reduce the vortex shedding, and as the width of the peak is increased, the vortices seem to decay faster. A similar observation was made by Yu and Yang [33] in their simulation.…”

“…Low turbulence levels mean less tonal noise and vice versa. In a recent study from Yu and Yang [33] it was shown that an oscillating trailing edge fringe is able to reduce the strength and size of the shed vortices, similar as observed for an active oscillation of the trailing edge reported by Simiriotis et al [34]. A flaplets, the short flaplets were also extremely effective at Re c > 600, 000.…”

Effect of the Extended Rigid Flapping Trailing Edge Fringe on an S833 Airfoil

“…As a result, it suppressed the leading-edge vortices approaching the flexible tail, and accelerated the shedding vortices' dissipation. Additionally, Yu et al (2020) performed computational fluid dynamics (CFD) simulations on an airfoil with an extended trailing-edge fringe [25]. The effects of the fringe lengths and flapping frequencies on shedding vortices have been investigated.…”

CFD Simulations and External Shape Optimization of Missile with Wing and Tailfin Configuration to Improve Aerodynamic Performance

“…For this, the airfoil was modified and computations were performed by means of SST k- turbulence model utilizing ANSYS Fluent. Another CFD simulation study was presented to increase aerodynamic performance reducing vorticity wake for S833 airfoil by Yu and Yang (2020). Numerical simulation was performed to investigate flapping wing aerodynamics by changing chord length by Kumar and Shah (2017).…”