A novel 3D variational aeroelastic framework for flexible multibody dynamics: Application to bat-like flapping dynamics

TL;DR

This paper introduces a comprehensive 3D variational aeroelastic framework combining fluid-structure interaction, turbulence modeling, and multibody dynamics to simulate flapping wings, validated against experimental data and applied to bat-like wing analysis.

Contribution

The paper develops a novel 3D variational aeroelastic framework integrating advanced fluid and structural solvers with force transfer techniques for flexible multibody systems.

Findings

Validated the framework with experimental data on aluminum wings.

Demonstrated robustness for anisotropic flapping wings with composite materials.

Analyzed the impact of flexibility on bat-like wing dynamics.

Abstract

We present a novel three-dimensional (3D) variational aeroelastic framework for flapping wing with a flexible multibody system subjected to an external incompressible turbulent flow. The proposed aeroelastic framework consists of a three-dimensional fluid solver with delayed detached eddy simulation (DDES) and a nonlinear monolithic elastic structural solver for the flexible multibody system with constraints. Radial basis function (RBF) is applied in this framework to transfer the aerodynamic forces and structural displacements across the discrete non-matching interface meshes while satisfying a global energy conservation. The fluid equations are discretized using a stabilized Petrov-Galerkin method in space and the generalized-$\alpha$ approach is employed to integrate the solution in time. The flexible multibody system is solved by using geometrically exact co-rotational finite element method and an energy decaying scheme is used to achieve numerical stability of the multibody solver with constraints. A nonlinear iterative force correction (NIFC) scheme is applied in a staggered partitioned iterative manner to maintain the numerical stability of aeroelastic coupling with strong added mass effect. An isotropic aluminum wing with flapping motion is simulated via the proposed aeroelastic framework and the accuracy of the coupled solution is validated with the available experimental data. We next study the robustness and reliability of the 3D flexible multibody aeroelastic framework for an anisotropic flapping wing flight involving battens and membranes with composite material and compare against the experimental results. Finally, we demonstrate the aeroelastic framework for a bat-like wing and examine the effects of flexibility on the flapping wing dynamics.