Aerodynamic investigation of three-dimensional �clap and fling� motion

The present study focuses on deciphering various aerodynamic phenomena and flow structures that explains the principles of lift generation in tiny insects. Simulations are performed on three-dimensional elliptical wings performing �clap and fling� motion based on the flight of Encasia Formosa. In this regard, a numerical fluid solver based on D3Q19 multiple relaxation time (MRT) model of lattice Boltzmann method (LBM) is developed. To justify the applicability of LBM on the moving boundaries, validations have been performed for the cases of hovering flat plate and sedimentation of a sphere in a fluid tank at different Reynolds numbers. The influence of the kinematic parameters such as rotational-translational overlap ? (0%-100%) and Reynolds number (Re=10 and Re=50) on the behaviour of lift and drag is examined. It is observed that overlap is the most influential parameter as lift to drag ratio at ?=100% is almost an order of magnitude higher than at ?=0% and is attributed to the attachment of a strong leadingedge vortex (LEV) during the clap phase in the former. Only a slight variation in lift to drag ratio is witnessed with Reynolds number for the small range considered in this work. � 2021, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.