CFD Validation of Small Quadrotor Performance using CREATE - AV Helios

Abstract

Computational fluid dynamics (CFD) simulations of a small quadrotor were conducted using CREATE™-AV Helios. Two near-body CFD solvers and multiple turbulence models including transition models available in Helios were tested. The DJI Phantom 3 was chosen as a representative configuration because it has been studied extensively and is typical of commercial unmanned aerial vehicles. The airfoil at three-quarters span of the rotor geometry was extracted to perform both two-dimensional (2D) airfoil and three-dimensional (3D) wing studies in order to determine appropriate grid spacings for use with the various models. Isolated rotor simulations for DJI Phantom 3 rotor in hover utilizing appropriate grids were completed for fully turbulent and turbulence transition models. The predicted thrust from all of the methods lie within experimental uncertainty. The Spalart Allmaras model gave consistent results across the two CFD solvers and was most computationally efficient. As such it was chosen for the simulations of the full quadrotor performance in hover. The results indicate that a transition model is not required in order to obtain satisfactory thrust predictions as compared to experiment for a small quadrotor in hover using the Helios package. However, the figure of merit is underpredicted by both fully turbulent and transition models. Therefore, the effect of transition modeling on torque prediction needs further investigation.