TY - GEN
T1 - Aeroacoustic predictions of the free-wake model, vortex particle method, and computational fluid dynamics for a coaxial rotor system
AU - Sharma, Kalki
AU - Brentner, Kenneth S.
AU - Jia, Zhongqi
AU - Lee, Seongkyu
AU - Anusonti-Inthra, Phuriwat
N1 - Funding Information:
Through VLRCOE, 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. Research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-20-2-0013. 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 Army Research Laboratory or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. The author would like to thank the High-Performance Internship Program (HIP) for providing funding and resources.
Funding Information:
Research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-20-2-0013. 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 Army Research Laboratory or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein.
Publisher Copyright:
Copyright © 2020 by the Vertical Flight Society. All rights reserved.
PY - 2020
Y1 - 2020
N2 - In this paper the aeroacoustic results using the Free-Wake Model (FWM), Vortex Particle Method (VPM), and Computational Fluid Dynamics (CFD) are compared with one another. The FWM and VPM is performed using the software Rotorcraft Comprehensive Analysis System (RCAS), and CFD analysis is performed using the software Helios. Analysis is performed on a lift-offset coaxial rotor system operating at 150 knots in forward flight and 0° shaft tilt. First, the blade loads are compared and then the acoustics using the noise prediction software PSU-WOPWOP. The major difference between the analysis methods is the manner in which they capture aerodynamic interactions. And the differences in the interactions result in differences in the acoustic results. The primary interactions are the blade vortex interactions (BVI), and the blade crossover interactions (BCI). The BVI events occur when a rotor operates in the wake of its own rotor or another rotor, and the BCI events occur when the blades of the upper and lower rotors cross one another. The BVI events are captured by all three methods, but there are variations in location and intensity between the three methods. On the other hand, the VPM and CFD capture the BCI events, but the VPM is unable to capture the BCI events on the retreating side of the upper rotor. These differences in the prediction of the interactions results in variations in directivity as well as intensity of the noise results. Upon analysis of the aeroacoustic results it is concluded that the inability of the FWM and VPM to capture some of the primary interactions capture by CFD can lead to major discrepancies between the acoustic results of the three methods.
AB - In this paper the aeroacoustic results using the Free-Wake Model (FWM), Vortex Particle Method (VPM), and Computational Fluid Dynamics (CFD) are compared with one another. The FWM and VPM is performed using the software Rotorcraft Comprehensive Analysis System (RCAS), and CFD analysis is performed using the software Helios. Analysis is performed on a lift-offset coaxial rotor system operating at 150 knots in forward flight and 0° shaft tilt. First, the blade loads are compared and then the acoustics using the noise prediction software PSU-WOPWOP. The major difference between the analysis methods is the manner in which they capture aerodynamic interactions. And the differences in the interactions result in differences in the acoustic results. The primary interactions are the blade vortex interactions (BVI), and the blade crossover interactions (BCI). The BVI events occur when a rotor operates in the wake of its own rotor or another rotor, and the BCI events occur when the blades of the upper and lower rotors cross one another. The BVI events are captured by all three methods, but there are variations in location and intensity between the three methods. On the other hand, the VPM and CFD capture the BCI events, but the VPM is unable to capture the BCI events on the retreating side of the upper rotor. These differences in the prediction of the interactions results in variations in directivity as well as intensity of the noise results. Upon analysis of the aeroacoustic results it is concluded that the inability of the FWM and VPM to capture some of the primary interactions capture by CFD can lead to major discrepancies between the acoustic results of the three methods.
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M3 - Conference contribution
AN - SCOPUS:85094915213
T3 - Aeromechanics for Advanced Vertical Flight Technical Meeting 2020, Held at Transformative Vertical Flight 2020
SP - 48
EP - 65
BT - Aeromechanics for Advanced Vertical Flight Technical Meeting 2020, Held at Transformative Vertical Flight 2020
PB - Vertical Flight Society
T2 - Aeromechanics for Advanced Vertical Flight Technical Meeting 2020, Held at Transformative Vertical Flight 2020
Y2 - 21 January 2020 through 23 January 2020
ER -