An Experimental Study to Quantify the Rotor-to-Rotor Interaction Characteristics of a Small Unmanned-Aerial-Vehicle


  • Wenwu Zhou Iowa State University
  • Zhe Ning Iowa State University
  • Hui Hu Iowa State University



Propeller Wake Characteristics, Rotor-to-Rotor interaction, Stereo PIV measurements


The flow interactions between laterally aligned rotors were investigated experimentally to study the rotor-to-rotor interactions on the aerodynamic and aeroacoustic performance of small unmanned aerial vehicles (UAVs). Two identical rotors, similar to the dimensions of Phantom 3 (DJI), were mounted separately on different stages in a wide-open space. High-accuracy force and sound measurements were conducted to document the thrust and noise at various separation distances. The detailed flow structures and corresponding vortex evolutions behind the rotors were resolved clearly by using high-resolution PIV measurements. As the rotor separation distance decreased, intensified flow interactions were noted within the rotors. More specifically, the twinrotor with separation distance of L= 0.05D exhibited a significantly enhanced thrust fluctuation (i.e., ~ 240% higher) and augmented noise level (i.e., ~ 3dB) in comparison with that of baseline case. Measured PIV results indicated that a strong recirculation region existed near the top-right of the twin-rotor case, which is believed to be the reason for the increased thrust fluctuations and aeroacoustic noise level.

Author Biography

Hui Hu, Iowa State University

Dr. Hui Hu is the Martin C. Jischke Professor of Aerospace Engineering at Iowa State University. His recent research interests include laser-based flow diagnostics; aircraft icing physics and anti-icing/de-icing technology; liquid fuel atomization and spray flow characterization; film cooling and thermal management of gas turbines; wind turbine aerodynamics and rotorcraft aeromechanics; micro-flows and micro-scale heat transfer in microfluidics.






Jets, Shear Layers and Wakes