Experimental characterization of UAS flow fields through hotwire anemometry and PIV

The velocity flow field around a small unmanned air system (UAS), specifically the DJI Phantom 3, is investigated in a series of experiments at Syracuse University. Experiments were conducted in the 15’x10’x18’ room herein referred to as the Indoor Flow Lab. The goal of these experiments was to gain a better understanding of the rich, turbulent flow field that a typical UAS creates. Characterization of the flow using hotwire anemometry and stereo particle image velocimetry (PIV) has been conducted. Regions of investigation include the downwash, above the vehicle, and far downstream. Investigation of several locations around the UAS show that dominant frequencies exist within the flow field. Analysis of the flow field includes calculation of mean velocities, turbulence intensities, mean-squared velocity, and turbulent kinetic energy at several downstream locations. The spectral content of the flow field is analyzed and presented using power spectral density. Discussion and comparison of the applicability of hotwire anemometry and stereo-PIV to this flow will be made.