High-Fidelity Computational Aerodynamics of Multi-Rotor Unmanned Aerial Vehicles

High-fidelity Computational Fluid Dynamics (CFD) simulations have been carried out for several multi-rotor Unmanned Aerial Vehicles (UAVs). Three vehicles have been studied: the classic quadcopter DJI Phantom 3, an unconventional quadcopter specialized for forward flight, the SUI Endurance, and an innovative concept for Urban Air Mobility (UAM), the Elytron 4S UAV. The three-dimensional unsteady Navier-Stokes equations are solved on overset grids using high-order accurate schemes, dual-time stepping, and a hybrid turbulence model. The DJI Phantom 3 is simulated with different rotors and with both a simplified airframe and the real airframe including landing gear and a camera. The effects of weather are studied for the DJI Phantom 3 quadcopter in hover. The SUI Endurance original design is compared in forward flight to a new configuration conceived by the authors, the hybrid configuration, which gives a large improvement in forward thrust. The Elytron 4S UAV is simulated in helicopter mode and in airplane mode. Understanding the complex flows in multi-rotor vehicles will help design quieter, safer, and more efficient future drones and UAM vehicles.

[1]  Caskey,et al.  GENERAL CIRCULATION EXPERIMENTS WITH THE PRIMITIVE EQUATIONS I . THE BASIC EXPERIMENT , 1962 .

[2]  Seokkwan Yoon,et al.  Simulations of XV-15 Rotor Flows in Hover Using OVERFLOW , 2014 .

[3]  Thomas Pulliam,et al.  High Order Accurate Finite-Difference Methods: as seen in OVERFLOW , 2011 .

[4]  Robert H. Nichols,et al.  Solver and Turbulence Model Upgrades to OVERFLOW 2 for Unsteady and High-Speed Applications , 2006 .

[5]  William M. Chan,et al.  Developments in Strategies and Software Tools for Overset Structured Grid Generation and Connectivity , 2011 .

[6]  P. Spalart.  Strategies for turbulence modelling and simulations , 2000 .

[7]  Seokkwan Yoon,et al.  Effect of Turbulence Modeling on Hovering Rotor Flows , 2015 .

[8]  James D. Baeder,et al.  Computational Investigation of Micro Hovering Rotor Aerodynamics , 2006 .

[9]  Keiji Nagatani,et al.  Reduction of Pitching Moment Generation of a Quadrotor UAV in Gust with Slant Rotors , 2017 .

[10]  Reynaldo J. Gomez.  Best Practices in Overset Grid Generation , 2002 .

[11]  Seokkwan Yoon,et al.  Computational Analysis of Multi-Rotor Flows , 2016 .

[12]  Casey L. Burley,et al.  Acoustic Characterization and Prediction of Representative, Small-Scale Rotary-Wing Unmanned Aircraft System Components , 2016 .

[13]  Colin R. Theodore,et al.  Computational Aerodynamic Modeling of Small Quadcopter Vehicles , 2017 .

[14]  J. Smagorinsky,et al.  GENERAL CIRCULATION EXPERIMENTS WITH THE PRIMITIVE EQUATIONS , 1963 .

[15]  Thomas H. Pulliam,et al.  Computations of Torque-Balanced Coaxial Rotor Flows , 2017 .

[16]  P. Spalart.  Comments on the feasibility of LES for wings, and on a hybrid RANS/LES approach , 1997 .