Computational and Experimental Aerodynamics of an E-VTOL Aircraft with Distributed Underwing Ducted Fan Propulsion and Boundary Layer Ingestion

In this study, computational fluid dynamic (CFD) simulations are performed on a novel eVTOL aircraft utilizing distributed underwing ducted fans for propulsion. The aircraft features a specially-designed highly undercambered airfoil, for the ducted fans to blend into the aft section of the airfoil and therefore be partially hidden when viewed from the front. It is theorized that this configuration can reduce form drag by decreasing the frontal area exposed to the freestream. The CFD model is represented by a half-body geometry of the eVTOL, and simulated at a speed of Mach 0.13 (162 km/h) resulting in a Reynolds number of 7x10(6) based on mean aerodynamic chord. The aerodynamic lift and drag coefficients were calculated and plotted for a wide range of angles of attack to determine the aerodynamic efficiency of the aircraft. The base drag coefficient is estimated as approximate to 0.06. Finally, RANS flowline simulations were conducted to evaluate the causes of the high base drag coefficient. It was discovered that considerable flow separation and some spanwise flow occurs on the underside of the airfoil at the cruise angle of attack of -4 degrees. A wind tunnel model is envisioned and developed for further validation of results.