Methods of analyzing isolated and ducted fixed-pitch propellers under non-axial inflow conditions

Currently, a growing interest for the propulsion of unmanned aerial vehicles (UAVs) can be recognized. To adress this, small-scale fixed-pitched propellers are analyzed in this work, both in isolated and ducted configurations. Due to their flight envelope, UAVs are likely to operate at highly inclined inflow conditions and even under reversed inflow, having a major influence on the flow field around a propeller. In order to investigate this influence, all analyses are performed at a range of inflow angles from αdisc = 0^◦ to 180^◦ relative to the propeller axis. This paper employs different numerical techniques and compares them regarding their capability of showing the influence of non-axial inflow on propeller configurations. Wind tunnel experiments are performed measuring the forces and visualizing the flow field with PIV as well as steady and unsteady RANS simulations are applied to study details of the flow field.