Flexible Wing of HALE UAV using Two-way Fluid Structure Interaction Method

Abstract

Simulation of High Altitude Long Endurance (HALE) UAV wing using two-way fluid structure interaction (FSI) method is presented. To achieve its mission, the HALE wing was designed to have high aspect ratio. With longer wing span, the HALE UAV may produce less induced drag and lift-loss which caused by the decrease in wingtip vortex strength. However, the wing structure with longer span becomes more elastic that may yield large deformation when aerodynamic loads applied. This deformation influences flow characteristics at the surrounding of the wing causing the change of aerodynamic loads distribution on the wing. Subsequently, this new load provides a new deformation to the wing structure and vice versa. This interaction in a couple process called as fluid structure interaction (FSI) of the HALE wing was simulated using ANSYS 15.0 software. The unsteadiness and viscous flows at low speed are evaluated using the solution of time-dependent Reynolds Averaged Navier-Stokes (RANS) with SST k-ω turbulent model. In addition, multi-block structured grids are generated to provide more accurate viscous result and to anticipate negative volume of the mesh which may occur due to the wing deformation during simulation. Five different simulations with variation of material characteristics including Young’s modulus and Poisson’s ratio are carried out. The results include global aerodynamic characteristics at various material characteristics.