Experimental and computational assessment of a ducted-fan rotor flow model

Ducted-fan-based vertical and/or short takeoff and landing uninhabited aerial vehicles are frequently encountered in aeronautical applications. In edgewise flight, the performance of these vehicles is, in general, poor because of the increasingly distorted inlet flow as the flight speed is increased. The present experimental study uses a planar particle image velocimeter system to investigate the near duct aerodynamic performance in hover and edgewise flight conditions. High-resolution particle image velocimetry measurements provide reliable and highresolution aerodynamic data forming a validation basis for further analytical and computational design studies. A radial equilibrium-based fan aerodynamic model is also integrated into a three-dimensional Reynold-averaged-Navier-Stokes-based computational system. Particle image velocimetry measurements and computational predictions of the mean flow near the fan inlet plane are in very good agreement at hover conditions. The aerodynamic modifications due to fan inlet flow distortion in an edgewise flight regime are clearly displayed in particle image velocimetry results. A comparison of the current particle image velocimetry measurements and the accelerated Reynold-averaged-Navier-Stokes predictions supported by the simple radial equilibrium-based rotor model indicates that the current rotor model can be highly effective and time efficient in the design cycle of future vertical and/or short takeoff and landing uninhabited aerial vehicle systems based on ducted fans.