Meeting Abstract

P1.119  Tuesday, Jan. 4  Effect of Wing Deformation on Butterfly Takeoff MAEDA, Masateru*; OZAWA, Shuhei; NAKATA, Toshiyuki; YANAOKA, Kazuhiro; LIU, Hao; Chiba University; Chiba University; Chiba University; HitachiSoft; Chiba University maz.maeda@graduate.chiba-u.jp

Butterfly takeoff simulations have been performed with different types of wings, i.e. rigid or deformable. We captured a swallowtail butterfly and the takeoff sequence was recorded with three high speed video cameras. From the images, we reconstructed the flight path of the insect as well as the deformation of the wings. We then performed 6 degrees of freedom (DOF) flight simulations based on the experiment. We have utilised a coupled solver of fluid dynamics and rigid-body dynamics so that free-flight rather than tethered-flight can be simulated, which is especially necessary for takeoff, a highly unsteady flight condition. The fluid dynamics part solves flow via three dimensional incompressible Navier-Stokes equations by means of finite volume method (FVM) and aerodynamic forces and torques are obtained. The rigid body dynamics part calculates the body movement due to the aerodynamic and gravitational forces and aerodynamic torques. A virtual “ground” is created by applying no-slip condition on the lower outer boundary of the Cartesian background grid. We also introduced the augmentation of the vertical and horizontal force by kicking the ground at the initial phase of takeoff, known as “leg thrust.” Two types of wings are examined: flat wings and deformable wings. The deformation of the wings has been prescribed from the measurement. The results show the enhancement of aerodynamic forces for the deformable wings.