Aerodynamic performance and flow mechanism of 3D flapping wing using discrete vortex method

TL;DR

This study uses the discrete vortex method to numerically analyze the aerodynamic performance and flow mechanisms of 3D flapping wings, including deformable configurations, revealing how wing deformation affects lift, thrust, and efficiency.

Contribution

It introduces a computational approach using DVM to study deformable 3D flapping wings and compares various deformation modes to enhance aerodynamic understanding.

Findings

Twisted wings improve both lift and thrust.

Bent wings increase lift but minimally affect thrust.

BTC wings are most efficient for aerodynamic performance.

Abstract

In this work, we have performed numerical simulations of the flapping motion of a rectangular wing in a three-dimensional flow field using the discrete vortex method (DVM). The DVM method is computationally more convenient because it does not require the generation of a grid for the flow field at each time step as in other conventional simulation methods. In addition to the rigid wing case, the aerodynamic characteristics of a deformable wing are also investigated. The deformable wing is studied in various configurations, such as bending, twisting, and bending-twisting coupling (BTC). The investigation of all four modes involves a detailed analysis of the flow mechanisms and vortex dynamics, which play a crucial role in influencing the aerodynamic forces, namely lift and thrust. The study aims to understand how these flow patterns change under different operating conditions and how these changes impact the generation of lift and thrust. The lift, thrust, and propulsive efficiency of all four modes are compared to provide a detailed understanding of their aerodynamic characteristics. The bent wing showed more lift compared to the rigid wing, but minimal improvements in thrust. In contrast, the twisted wing showed greater improvements in both lift and thrust. The BTC wing proves to be the most efficient method to improve aerodynamic performance during flapping. The parametric dependence of kinematic parameters such as asymmetric ratio (downstroke speed to upstroke speed), aspect ratio and reduced frequency on the aerodynamic performance was also investigated.