Large dynamic pitching for lift enhancement during the pull-out manoeuvre of raptors

From classical mechanics the lift coefficient, [Formula: see text], required during the final stage of the pull-out manoeuvre of raptors is significantly larger than those provided under static pitch condition at equivalent angle of attack. Using data from observation in live experiments and wind-tunnel on static models, coupled with our current numerical study, we demonstrated that the high lift is achieved through dynamic pitching while engaging into the pull-up. Computational fluid dynamics (CFD) simulations using a direct numerical simulation (DNS) approach with a Lattice-Boltzmann method (LBM), as well as unsteady Reynolds Averaged Navier-Stokes (URANS) simulations were performed over a [Formula: see text] swept non-slender delta wing, inspired by previous studies which showed that the flow over Peregrine falcons is dominated by large vortical structures. Here we show that, raptors potentially engage into dynamic pitching to meet the [Formula: see text] requirement under load factors n > 1 in order to achieve the high lift coefficient required during pull-up. Whilst it is a well-established fact for pitching wings, to our knowledge, this has not been extended to the observations in nature and could be therefore extended for application on nature inspired autonomous aerial vehicles or systems.