Seminar: A Computational Aerodynamic and Aeroacoustic Study of Small-Scale Rotor Geometries

Abstract

Drones, or micro aerial vehicles, are becoming more popular due to their many commercial applications and their use by hobbyists. Specifically, the drones that are the most popular are of the multi-copter design; thus, research should be geared towards these configurations. With an increase in the number of drones and their interactions with people, the annoyance due to sound becomes an issue. Furthermore, full-scale rotors at high Reynolds numbers (greater than 106) have been designed to achieve high figure of merit (the ratio of ideal power to actual power) around 0.8, but the same cannot be said for small-scale low Reynolds numbers (104 to 105) rotors, which are less aerodynamically efficient. Consequently, there is room for improvement in terms of aerodynamic and acoustic performance of multi-copter drones. To explore this issue, a parametric design study was conducted using common rotor design variables. This study involved varying values of parameters such as chord length, angle of attack (or pitch), blade number, twist, taper and thickness to understand how they impact aerodynamic and acoustic performance. In addition, various tip geometries such as winglets and other noise suppression tip designs were tested to understand their aerodynamic and acoustic impact at this small-scale. Performance metrics such as power loading (ratio of thrust to power), figure of merit and others were used to judge aerodynamic performance of the different designs. Metrics such as one-third octave band data and overall sound pressure level, among others, were calculated at two different receivers in the far-field to compare acoustic performance of the different rotor designs. Flow fields and pressure contours were provided to help explain the aerodynamic and acoustic results from the various rotor designs. With the results from this study, ample insights are provided such that small-scale rotors can be designed to be more aerodynamically and acoustically efficient.

About the speaker

Quinten Henricks is a recent graduate from The Ohio State University where he received his masters degree in mechanical engineering. He is currently a graduate research associate and conducts computational research on small-scale rotor aerodynamics and acoustics.  

Hosted by Prof. Mei Zhang.