Numerical Study on Tandem-Rotor Autorotation in Forward Flight
This work presents a systematic approach to analyzing the aerodynamic characteristics of tandem rotor forward autorotation considering rotor-to-rotor interference. The single-rotor computational model trimmed from a generic helicopter flight dynamics analysis program was used as the baseline model....
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-12-01
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| Series: | Aerospace |
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| Online Access: | https://www.mdpi.com/2226-4310/10/1/15 |
| _version_ | 1797431054949154816 |
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| author | Jiayu Wen Yanguo Song Huanjin Wang Dong Han |
| author_facet | Jiayu Wen Yanguo Song Huanjin Wang Dong Han |
| author_sort | Jiayu Wen |
| collection | DOAJ |
| description | This work presents a systematic approach to analyzing the aerodynamic characteristics of tandem rotor forward autorotation considering rotor-to-rotor interference. The single-rotor computational model trimmed from a generic helicopter flight dynamics analysis program was used as the baseline model. The effectiveness of the baseline model is demonstrated by a comparison with data from wind tunnel tests performed in this work. The rotor disk angle of attack and driven moment distribution obtained by the modified model indicate the fact that the rotor acceleration is primarily caused by the higher angle of attack region of the disk. This is of great significance in the rotor blade design, in terms of the drag-to-lift ratio characteristics of the airfoil under different angle-of-attack ranges. The influence of wind speed, rotor shaft angle, and collective pitch on the steady-state rotor speed was then studied. The results show a nonlinear nature of the variation of steady rotor speed with collective pitch, which can cause a thrust control reverse problem during flight operations. To reveal the flow field details of rotor-to-rotor interference, the flow field Navier–Stokes equations of tandem rotor autorotation were solved. Computational results of both rotors’ inflow velocities were considered when deriving the empirical model of interference. The refined interference model was compared to the wind tunnel test data of the tandem rotor autorotation and showed good performance. This synthetical methodology, which combines mechanism analysis with CFD-aided refinement and experiment verification, achieves a balance between computational costs and accuracy and thus can be readily applied to engineering practices. |
| first_indexed | 2024-03-09T09:37:24Z |
| format | Article |
| id | doaj.art-08d07ee213c64feeac501473f03cb9d5 |
| institution | Directory Open Access Journal |
| issn | 2226-4310 |
| language | English |
| last_indexed | 2024-03-09T09:37:24Z |
| publishDate | 2022-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Aerospace |
| spelling | doaj.art-08d07ee213c64feeac501473f03cb9d52023-12-02T01:15:49ZengMDPI AGAerospace2226-43102022-12-011011510.3390/aerospace10010015Numerical Study on Tandem-Rotor Autorotation in Forward FlightJiayu Wen0Yanguo Song1Huanjin Wang2Dong Han3College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210001, ChinaCollege of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210001, ChinaCollege of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210001, ChinaCollege of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210001, ChinaThis work presents a systematic approach to analyzing the aerodynamic characteristics of tandem rotor forward autorotation considering rotor-to-rotor interference. The single-rotor computational model trimmed from a generic helicopter flight dynamics analysis program was used as the baseline model. The effectiveness of the baseline model is demonstrated by a comparison with data from wind tunnel tests performed in this work. The rotor disk angle of attack and driven moment distribution obtained by the modified model indicate the fact that the rotor acceleration is primarily caused by the higher angle of attack region of the disk. This is of great significance in the rotor blade design, in terms of the drag-to-lift ratio characteristics of the airfoil under different angle-of-attack ranges. The influence of wind speed, rotor shaft angle, and collective pitch on the steady-state rotor speed was then studied. The results show a nonlinear nature of the variation of steady rotor speed with collective pitch, which can cause a thrust control reverse problem during flight operations. To reveal the flow field details of rotor-to-rotor interference, the flow field Navier–Stokes equations of tandem rotor autorotation were solved. Computational results of both rotors’ inflow velocities were considered when deriving the empirical model of interference. The refined interference model was compared to the wind tunnel test data of the tandem rotor autorotation and showed good performance. This synthetical methodology, which combines mechanism analysis with CFD-aided refinement and experiment verification, achieves a balance between computational costs and accuracy and thus can be readily applied to engineering practices.https://www.mdpi.com/2226-4310/10/1/15tandem helicopterautorotationrotor-to-rotor interferencewind tunnel experimentcomputational fluid dynamicsflight dynamics |
| spellingShingle | Jiayu Wen Yanguo Song Huanjin Wang Dong Han Numerical Study on Tandem-Rotor Autorotation in Forward Flight Aerospace tandem helicopter autorotation rotor-to-rotor interference wind tunnel experiment computational fluid dynamics flight dynamics |
| title | Numerical Study on Tandem-Rotor Autorotation in Forward Flight |
| title_full | Numerical Study on Tandem-Rotor Autorotation in Forward Flight |
| title_fullStr | Numerical Study on Tandem-Rotor Autorotation in Forward Flight |
| title_full_unstemmed | Numerical Study on Tandem-Rotor Autorotation in Forward Flight |
| title_short | Numerical Study on Tandem-Rotor Autorotation in Forward Flight |
| title_sort | numerical study on tandem rotor autorotation in forward flight |
| topic | tandem helicopter autorotation rotor-to-rotor interference wind tunnel experiment computational fluid dynamics flight dynamics |
| url | https://www.mdpi.com/2226-4310/10/1/15 |
| work_keys_str_mv | AT jiayuwen numericalstudyontandemrotorautorotationinforwardflight AT yanguosong numericalstudyontandemrotorautorotationinforwardflight AT huanjinwang numericalstudyontandemrotorautorotationinforwardflight AT donghan numericalstudyontandemrotorautorotationinforwardflight |