Numerical simulation of flapping wings using a panel method and a high-order Navier-Stokes solver

The design of efficient flapping wings for human engineered micro aerial vehicles (MAVs) has long been an elusive goal, in part because of the large size of the design space. One strategy for overcoming this difficulty is to use a multifidelity simulation strategy that appropriately balances computation time and accuracy. We compare two models with different geometric and physical fidelity. The low-fidelity model is an inviscid doublet lattice method with infinitely thin lifting surfaces. The high-fidelity model is a high-order accurate discontinuous Galerkin Navier-Stokes solver, which uses an accurate representation of the flapping wing geometry. To compare the performance of the two methods, we consider a model flapping wing with an elliptical planform and an analytically prescribed spanwise wing twist, at size scales relevant to MAVs. Our results show that in many cases, including those with mild separation, low-fidelity simulations can accurately predict integrated forces, provide insight into the flow structure, indicate regions of likely separation, and shed light on design-relevant quantities. But for problems with significant levels of separation, higher-fidelity methods are required to capture the details of the flow field. Inevitably high-fidelity simulations are needed to establish the limits of validity of the lower fidelity simulations.Copyright (c) 2012 John Wiley & Sons, Ltd.