Rotor–duct aerodynamic and acoustic interactions at low Reynolds number
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Ducted single and multi-rotor UAVs (unmanned aerial vehicle) offer better crash worthiness and safety compared to open rotor UAVs. The interactions that affect performance and acoustics are of interest. High speed stereo particle image velocimetry (SPIV), performance, and acoustic measurements were done on a rotor with removable protective duct to study rotor–duct aerodynamic interactions over a range of hover conditions at low Reynolds number. Instantaneous and averaged SPIV velocity field and performance results, as well as acoustic signatures, are compared to baseline un-ducted rotor cases. Increase in rotor figure of merit is strongly correlated with the level of duct interaction with rotor tip vortex cores. Efficiency change is higher for the cases where thrust induced losses take a larger share of the overall aerodynamic losses. While the overall acoustic sound pressure level was not affected significantly, cases with higher vortex core/duct interactions showed higher tonal content.
This research was partially funded by the Government Vertical Lift Rotorcraft Centers of Excellence, under Agreement no. W911W6-17-2-0002. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation thereon. The U.S. Government technical monitor is Mahendra Bhagwat. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Aviation Development Directorate or the U.S. Government. We would also like to thank Dr. Nandeesh Hiremath for his help in acoustic tests and the team of undergraduate researchers in the Experimental Aerodynamics lab at Georgia Tech for their assistance in building the setup and tests.
- Akturk A, Shavalikul A, Camci C (2008) PIV measurements and computational study of a 5-inch ducted fan for V/STOL UAV applications. In: 47th AIAA aerospace sciences meeting including the new horizons forum and aerospace exposition, p 332Google Scholar
- Bohorquez F (2007) Rotor hover performance and system design of an efficient coaxial rotary wing micro air vehicle. Doctoral dissertationGoogle Scholar
- Graftieaux L, Michard M, Grosjean N (2001) Combining PIV, POD and vortex identification algorithms for the study of unsteady turbulent swirling flows. Meas Sci Technol 12(9):1422. http://iopscience.iop.org/article/10.1088/0957-0233/12/9/307/pdf
- Heineck JT, Wadcock AJ, Yamauchi GK, Lourenco L, Abrego AI (2000) Application of three-component PIV to a hovering rotor wake. National Aeronautics and Space Administration Moffett Field CA AMES Research Center, CaliforniaGoogle Scholar
- Hrishikeshavan V (2011) Experimental investigation of shrouded rotor micro air vehicle in hover and in edgewise gusts, Doctoral dissertationGoogle Scholar
- Kunz P, Stawn R (2003) Analysis and design of rotors at ultra-low Reynolds numbers. In: 40th AIAA aerospace sciences meeting & exhibit, p 99Google Scholar
- Landgrebe AJ (1971) An analytical and experimental investigation of helicopter rotor hover performance and wake geometry characteristics (no. K910828-31). United Aircraft Research Labs, East Hartford, CTGoogle Scholar
- Martin P, Tung C (2004) Performance and flowfield measurements on a 10-inch ducted rotor VTOL UAV. Army Research Development and Engineering Command Moffett Field CA Aviation Aeroflight Dynamics DirectorateGoogle Scholar
- Pereira JL (2008) Hover and wind-tunnel testing of shrouded rotors for improved micro air vehicle design. Department of Aerospace Engineering, Maryland University College Park, College ParkGoogle Scholar
- Shukla D, Hiremath N, Patel S, Komerath N (2017) Aerodynamic interactions study on low-Re coaxial and quad-rotor configurations. In: ASME 2017 international mechanical engineering congress and exposition. American Society of Mechanical Engineers, pp V007T09A023–V007T09A023Google Scholar
- Shukla D, Hiremath N, Komerath NM (2018) Low Reynolds number aerodynamics study on coaxial and quad-rotor. In: Applied aerodynamics conference, AIAA aviation and aeronautics forum and exposition 2018, p 4118Google Scholar