Abstract
Rotor hub parasite drag remains one of the challenges in further improving the forward-flight capabilities of coaxial rotorcraft. Comprehensive datasets on notional coaxial hub configurations are rare, and more so at Reynolds numbers sufficiently high to preserve dominating flow structures downstream into the wake where they interact with the rotorcraft empennage and tail. The present investigation was designed specifically to improve the understanding of interactional aerodynamics effects and wake flow physics of counter-rotating coaxial rotor hubs. A unique dataset is presented on a rotor hub design equipped with the DBLN 526 airfoil at a diameter-based Reynolds number of 1.13x106, corresponding to approximately quarter-scale Reynolds conditions of a coaxial compound helicopter at 200 knots. The experiments measured the time-averaged and time-varying drag on the hub configuration, with focus on a cruise advance ratio of 0.25 and a high-speed condition at 0.60. In addition to measuring hub drag and its harmonic content, a unique aspect of the experiment was the use of multiple non-invasive flow-diagnostics techniques for the particular hub configuration, advance ratios, and Reynolds number. Specifically, stereoscopic particle-image velocimetry (SPIV) measured the three velocity components at two downstream locations in the hub wake, thus providing insight into and visualizing the development of the wake. In addition, a limited laser-doppler velocimetry (LDV) and a tomographic PIV (Tomo-PIV) data campaign were conducted that confirm the earlier SPIV measurements. A subset of all measurements is presented. Some new insight into the flow physics was gained, one example being the dependence of higher-harmonic per-rev flow structures in the wake on hub advance ratio.
| Original language | English (US) |
|---|---|
| Title of host publication | Vertical Flight Society 80th Annual Forum and Technology Display |
| Publisher | Vertical Flight Society |
| ISBN (Electronic) | 9781713897941 |
| State | Published - 2024 |
| Event | 80th Annual Vertical Flight Society Forum and Technology Display, FORUM 2024 - Montreal, Canada Duration: May 7 2024 → May 9 2024 |
Publication series
| Name | Vertical Flight Society 80th Annual Forum and Technology Display |
|---|
Conference
| Conference | 80th Annual Vertical Flight Society Forum and Technology Display, FORUM 2024 |
|---|---|
| Country/Territory | Canada |
| City | Montreal |
| Period | 5/7/24 → 5/9/24 |
All Science Journal Classification (ASJC) codes
- Aerospace Engineering
- Control and Systems Engineering
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Schmitz, S., Jaffa, N., Reich, D., Nickels, A., Pabon, R., Piqué, A., & Durachko, T. (2024). Flow Diagnostics of Scaled-Model Coaxial Rotor Hub Flows. In Vertical Flight Society 80th Annual Forum and Technology Display (Vertical Flight Society 80th Annual Forum and Technology Display). Vertical Flight Society.
Schmitz, Sven ; Jaffa, Nicholas ; Reich, David et al. / Flow Diagnostics of Scaled-Model Coaxial Rotor Hub Flows. Vertical Flight Society 80th Annual Forum and Technology Display. Vertical Flight Society, 2024. (Vertical Flight Society 80th Annual Forum and Technology Display).
@inproceedings{57fd648d71254e709274447e23845001,
title = "Flow Diagnostics of Scaled-Model Coaxial Rotor Hub Flows",
abstract = "Rotor hub parasite drag remains one of the challenges in further improving the forward-flight capabilities of coaxial rotorcraft. Comprehensive datasets on notional coaxial hub configurations are rare, and more so at Reynolds numbers sufficiently high to preserve dominating flow structures downstream into the wake where they interact with the rotorcraft empennage and tail. The present investigation was designed specifically to improve the understanding of interactional aerodynamics effects and wake flow physics of counter-rotating coaxial rotor hubs. A unique dataset is presented on a rotor hub design equipped with the DBLN 526 airfoil at a diameter-based Reynolds number of 1.13x106, corresponding to approximately quarter-scale Reynolds conditions of a coaxial compound helicopter at 200 knots. The experiments measured the time-averaged and time-varying drag on the hub configuration, with focus on a cruise advance ratio of 0.25 and a high-speed condition at 0.60. In addition to measuring hub drag and its harmonic content, a unique aspect of the experiment was the use of multiple non-invasive flow-diagnostics techniques for the particular hub configuration, advance ratios, and Reynolds number. Specifically, stereoscopic particle-image velocimetry (SPIV) measured the three velocity components at two downstream locations in the hub wake, thus providing insight into and visualizing the development of the wake. In addition, a limited laser-doppler velocimetry (LDV) and a tomographic PIV (Tomo-PIV) data campaign were conducted that confirm the earlier SPIV measurements. A subset of all measurements is presented. Some new insight into the flow physics was gained, one example being the dependence of higher-harmonic per-rev flow structures in the wake on hub advance ratio.",
author = "Sven Schmitz and Nicholas Jaffa and David Reich and Adam Nickels and Rommel Pabon and Alexander Piqu{\'e} and Tim Durachko",
note = "Publisher Copyright: Copyright {\textcopyright} 2024 by the Vertical Flight Society. All rights reserved.; 80th Annual Vertical Flight Society Forum and Technology Display, FORUM 2024 ; Conference date: 07-05-2024 Through 09-05-2024",
year = "2024",
language = "English (US)",
series = "Vertical Flight Society 80th Annual Forum and Technology Display",
publisher = "Vertical Flight Society",
booktitle = "Vertical Flight Society 80th Annual Forum and Technology Display",
}
Schmitz, S, Jaffa, N, Reich, D, Nickels, A, Pabon, R, Piqué, A & Durachko, T 2024, Flow Diagnostics of Scaled-Model Coaxial Rotor Hub Flows. in Vertical Flight Society 80th Annual Forum and Technology Display. Vertical Flight Society 80th Annual Forum and Technology Display, Vertical Flight Society, 80th Annual Vertical Flight Society Forum and Technology Display, FORUM 2024, Montreal, Canada, 5/7/24.
Flow Diagnostics of Scaled-Model Coaxial Rotor Hub Flows. / Schmitz, Sven; Jaffa, Nicholas; Reich, David et al.
Vertical Flight Society 80th Annual Forum and Technology Display. Vertical Flight Society, 2024. (Vertical Flight Society 80th Annual Forum and Technology Display).
Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
TY - GEN
T1 - Flow Diagnostics of Scaled-Model Coaxial Rotor Hub Flows
AU - Schmitz, Sven
AU - Jaffa, Nicholas
AU - Reich, David
AU - Nickels, Adam
AU - Pabon, Rommel
AU - Piqué, Alexander
AU - Durachko, Tim
N1 - Publisher Copyright:Copyright © 2024 by the Vertical Flight Society. All rights reserved.
PY - 2024
Y1 - 2024
N2 - Rotor hub parasite drag remains one of the challenges in further improving the forward-flight capabilities of coaxial rotorcraft. Comprehensive datasets on notional coaxial hub configurations are rare, and more so at Reynolds numbers sufficiently high to preserve dominating flow structures downstream into the wake where they interact with the rotorcraft empennage and tail. The present investigation was designed specifically to improve the understanding of interactional aerodynamics effects and wake flow physics of counter-rotating coaxial rotor hubs. A unique dataset is presented on a rotor hub design equipped with the DBLN 526 airfoil at a diameter-based Reynolds number of 1.13x106, corresponding to approximately quarter-scale Reynolds conditions of a coaxial compound helicopter at 200 knots. The experiments measured the time-averaged and time-varying drag on the hub configuration, with focus on a cruise advance ratio of 0.25 and a high-speed condition at 0.60. In addition to measuring hub drag and its harmonic content, a unique aspect of the experiment was the use of multiple non-invasive flow-diagnostics techniques for the particular hub configuration, advance ratios, and Reynolds number. Specifically, stereoscopic particle-image velocimetry (SPIV) measured the three velocity components at two downstream locations in the hub wake, thus providing insight into and visualizing the development of the wake. In addition, a limited laser-doppler velocimetry (LDV) and a tomographic PIV (Tomo-PIV) data campaign were conducted that confirm the earlier SPIV measurements. A subset of all measurements is presented. Some new insight into the flow physics was gained, one example being the dependence of higher-harmonic per-rev flow structures in the wake on hub advance ratio.
AB - Rotor hub parasite drag remains one of the challenges in further improving the forward-flight capabilities of coaxial rotorcraft. Comprehensive datasets on notional coaxial hub configurations are rare, and more so at Reynolds numbers sufficiently high to preserve dominating flow structures downstream into the wake where they interact with the rotorcraft empennage and tail. The present investigation was designed specifically to improve the understanding of interactional aerodynamics effects and wake flow physics of counter-rotating coaxial rotor hubs. A unique dataset is presented on a rotor hub design equipped with the DBLN 526 airfoil at a diameter-based Reynolds number of 1.13x106, corresponding to approximately quarter-scale Reynolds conditions of a coaxial compound helicopter at 200 knots. The experiments measured the time-averaged and time-varying drag on the hub configuration, with focus on a cruise advance ratio of 0.25 and a high-speed condition at 0.60. In addition to measuring hub drag and its harmonic content, a unique aspect of the experiment was the use of multiple non-invasive flow-diagnostics techniques for the particular hub configuration, advance ratios, and Reynolds number. Specifically, stereoscopic particle-image velocimetry (SPIV) measured the three velocity components at two downstream locations in the hub wake, thus providing insight into and visualizing the development of the wake. In addition, a limited laser-doppler velocimetry (LDV) and a tomographic PIV (Tomo-PIV) data campaign were conducted that confirm the earlier SPIV measurements. A subset of all measurements is presented. Some new insight into the flow physics was gained, one example being the dependence of higher-harmonic per-rev flow structures in the wake on hub advance ratio.
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M3 - Conference contribution
AN - SCOPUS:85196750208
T3 - Vertical Flight Society 80th Annual Forum and Technology Display
BT - Vertical Flight Society 80th Annual Forum and Technology Display
PB - Vertical Flight Society
T2 - 80th Annual Vertical Flight Society Forum and Technology Display, FORUM 2024
Y2 - 7 May 2024 through 9 May 2024
ER -
Schmitz S, Jaffa N, Reich D, Nickels A, Pabon R, Piqué A et al. Flow Diagnostics of Scaled-Model Coaxial Rotor Hub Flows. In Vertical Flight Society 80th Annual Forum and Technology Display. Vertical Flight Society. 2024. (Vertical Flight Society 80th Annual Forum and Technology Display).
