TY - GEN
T1 - Scaled model testing of coaxial rotor hub flows
AU - Tierney, Charles
AU - Reich, David
AU - Jaffa, Nicholas
AU - Schmitz, Sven
N1 - Funding Information:
This research was partially funded by the Government under Agreement No. W911W6-17-2-0003. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation thereon. 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.
Publisher Copyright:
Copyright © 2021 by the Vertical Flight Society. All rights reserved.
PY - 2021
Y1 - 2021
N2 - Rotor hub parasite drag remains a primary obstacle to improving the forward-flight capabilities of helicopters. As part of a rotor hub flow physics project at the Vertical Lift Research Center of Excellence (VLRCOE) at Penn State, this investigation was designed to improve the understanding of the interactional aerodynamics and wake flow physics of counter-rotating coaxial rotor hubs and explore designs for reducing the rotor hub drag factor, KKfefeee. These experiments measured the time-averaged and time-varying drag on four rotor hub designs, each with unique blade stubs. The four shapes tested were the DBLN 526 airfoil, 3.25:1 Rectangle, 4:1 Ellipse, and the novel profile named the Optimized Cambered Shape (OCS). Load data was collected at four Reynolds numbers ranging from 3.77 × 105 to 1.51 × 106 and advance ratios ranging from .25 to .6. Additionally, stereoscopic particle-image velocimetry (SPIV) measured the three velocity components at two downstream locations in the wake of the DBLN 526 rotor hub at RRee = 1.13 × 106 and advance ratios of .25 and .6, providing insight into and visualizing the development of the wake. Presented here is the compiled load data and calculated KKfefee from these experiments, as well as the flow fields at the near- and mid-wake locations, with discussion of new knowledge gained of the coaxial rotor hub wakes.
AB - Rotor hub parasite drag remains a primary obstacle to improving the forward-flight capabilities of helicopters. As part of a rotor hub flow physics project at the Vertical Lift Research Center of Excellence (VLRCOE) at Penn State, this investigation was designed to improve the understanding of the interactional aerodynamics and wake flow physics of counter-rotating coaxial rotor hubs and explore designs for reducing the rotor hub drag factor, KKfefeee. These experiments measured the time-averaged and time-varying drag on four rotor hub designs, each with unique blade stubs. The four shapes tested were the DBLN 526 airfoil, 3.25:1 Rectangle, 4:1 Ellipse, and the novel profile named the Optimized Cambered Shape (OCS). Load data was collected at four Reynolds numbers ranging from 3.77 × 105 to 1.51 × 106 and advance ratios ranging from .25 to .6. Additionally, stereoscopic particle-image velocimetry (SPIV) measured the three velocity components at two downstream locations in the wake of the DBLN 526 rotor hub at RRee = 1.13 × 106 and advance ratios of .25 and .6, providing insight into and visualizing the development of the wake. Presented here is the compiled load data and calculated KKfefee from these experiments, as well as the flow fields at the near- and mid-wake locations, with discussion of new knowledge gained of the coaxial rotor hub wakes.
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M3 - Conference contribution
AN - SCOPUS:85108974512
T3 - 77th Annual Vertical Flight Society Forum and Technology Display, FORUM 2021: The Future of Vertical Flight
BT - 77th Annual Vertical Flight Society Forum and Technology Display, FORUM 2021
PB - Vertical Flight Society
T2 - 77th Annual Vertical Flight Society Forum and Technology Display: The Future of Vertical Flight, FORUM 2021
Y2 - 10 May 2021 through 14 May 2021
ER -