Characterisation and extension of a rigid body dynamics solver coupled with OpenFOAM for flight performance analysis of flapping-wing drones

TL;DR

This paper develops and verifies a coupled rigid body and CFD solver in OpenFOAM for flapping-wing drone flight analysis, addressing performance and control limitations for better simulation fidelity.

Contribution

It introduces a validated, efficient CFD-robot dynamics coupling in OpenFOAM, enabling realistic, parametric, and real-time flight simulations of flapping-wing drones.

Findings

The solver accurately simulates ascending flight with LES turbulence modeling.

Grid and scheme independence are demonstrated through parametric studies.

Overset grid method identified as the main computational bottleneck.

Abstract

The extraordinary aerial agility of hummingbirds and insects continues to inspire the design of flapping-wing drones. To replicate and analyze such flight, computational fluid dynamics (CFD) simulations that couple flow solvers with rigid body dynamics are essential. While OpenFOAM offers tools for these multiphysics simulations, two key limitations remain: (1) a lack of thorough verification and performance characterization, and (2) the reliance on torque-based control for wing motion, which is impractical for parametric studies and real-time control. The developments are tested with a four and a five degrees of freedom flapping-wing drone equipped with a rigid, semi-elliptical wing. Ascending flight motions are simulated using the overset method, a moving background grid, and an LES model. Parametric studies demonstrate the independence of the grid and integration schemes, while profiling analyses identify the overset method as the computational bottleneck. The drone trajectories are compared with those from a literature quasi-steady model, and the body-wing interaction is analyzed in detail.