Insects fly even under heavy turbulent air flow conditions. To understand the impact of turbulent fluctuations on the aerodynamics of flapping wings, we model a bumblebee with fixed body and prescribed wing motion, flying in a numerical wind tunnel. The inflow condition of the tunnel varies from unperturbed laminar to strongly turbulent. Massively parallel simulations show that turbulence does not significantly alter the wing's leading edge vortex that is required for elevated lift production. Mean flight forces, moments and aerodynamic power expenditures are thus unaffected, suggesting little significance of turbulence on overall flight performance in insects. The increase in variance of the aerodynamic measures with increasing turbulence intensity, however, leads to flight instabilities in freely flying animals. This is joint work with Thomas Engels, Dmitry Kolomeskiy, Fritz-Olaf Lehmann and Jorn Sesterhenn.
T. Engels, D. Kolomenskiy, K. Schneider, F.O. Lehmann and J. Sesterhenn. Bumblebee flight in heavy turbulence. Phys. Rev. Lett., 116, 028103, 2016.
T. Engels, D. Kolomenskiy, K. Schneider and J. Sesterhenn. FluSI: A novel parallel simulation tool for flapping insect flight using a Fourier method with volume penalization. SIAM J. Sci. Comput., 2016, in press.