Computational Investigation of Coaxial Rotor Interactional Aerodynamics in Steady Forward Flight

2015 ◽  
Author(s):  
Bradley J. Passe ◽  
Ananth Sridharan ◽  
James D. Baeder
Keyword(s):  
Computational Investigation ◽  
Forward Flight ◽  
Coaxial Rotor

scholarly journals Computational Investigation of Microscale Coaxial-Rotor Aerodynamics in Hover

2010 ◽  
Vol 47 (3) ◽  
pp. 940-955 ◽  
Author(s):  
Vinod K. Lakshminarayan ◽  
James D. Baeder
Keyword(s):  
Computational Investigation ◽  
Rotor Aerodynamics ◽  
Coaxial Rotor

scholarly journals A computational investigation of lift generation and power expenditure of Pratt’s roundleaf bat (Hipposideros pratti) in forward flight

PLoS ONE ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. e0207613 ◽  
Author(s):  
Peter Windes ◽  
Xiaozhou Fan ◽  
Matt Bender ◽  
Danesh K. Tafti ◽  
Rolf Müller
Keyword(s):  
Computational Investigation ◽  
Forward Flight ◽  
Power Expenditure

scholarly journals Wind Tunnel Studies on Hover and Forward Flight Performances of a Coaxial Rigid Rotor

Aerospace ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 205
Author(s):  
Chang Wang ◽  
Minqi Huang ◽  
Xianmin Peng ◽  
Guichuan Zhang ◽  
Min Tang ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Tilt Angle ◽  
Lift Coefficient ◽  
Rotor System ◽  
Rigid Rotor ◽  
Forward Flight ◽  
Coaxial Rotor ◽  
Advance Ratio ◽  
Hover Flight ◽  
Development Center

The aerodynamic performance of a reduced-scale coaxial rigid rotor system in hover and steady forward flights was experimentally investigated to gain insights into the effect of interference between upper and lower rotors and the influences of the advance ratio, shaft tilt angle and lift offset. The rotor system featured by 2 m-diameter, four-bladed upper and lower hingeless rotors and was installed in a coaxial rotor test rig. Experiments were conducted in the Φ3.2 m wind tunnel at China Aerodynamics Research and Development Center (CARDC). The rotor system was tested in hover states at collective pitches ranging from 0° to 13° and it was also tested in forward flights at advance ratios up to 0.6, with specific focus on the shaft tilt angle and lift offset sweeps. To ensure that the coaxial rotor was operating in a similar manner to that of the real flight, the torque difference was trimmed to zero in hover flight, whilst the constant lift coefficient was maintained in forward flight. An isolated single-rotor configuration test was also conducted with the same pitch angle setting in the coaxial rotor. The hover test results demonstrate that the figure of merit (FM) value of the lower rotor is lower than that of the upper rotor, and both are lower than that of the isolated single rotor. Moreover, the coaxial rotor configuration can contribute to better hover efficiency under the same blade loading coefficient (CT/σ). In forward flight, the effective lift-to-drag (L/De) ratio of the coaxial rigid rotor does not monotonously change as the advance ratio increases. Increases in the required power and drag in the case with a high advance ratio of 0.6 leads to the decreasing L/De ratio of the rotor. Meanwhile, the L/De ratio of the rotor is relatively high when the rotor shaft is tilted backward. The increasing lift offset tends to result in reduced required rotor power and an increase in the rotor drag. When the effect of the reduced rotor power is greater than that of the increased rotor drag, the L/De ratio increases as the lift offset increases. The L/De ratio can benefit significantly from lift offset at a high advance ratio, but it is much less influenced by lift offset at a low advance ratio. The forward performance efficiency of the upper rotor is poorer than that of the lower rotor, which is significantly different from the case in the hover flight.

scholarly journals Aerodynamic Simulation of Helicopter Based on Polyhedron Nested Grid Technology

2020 ◽  
Vol 10 (22) ◽  
pp. 8304
Author(s):  
Chenglong Zhou ◽  
Ming Chen
Keyword(s):  
Flow Field ◽  
Cfd Simulation ◽  
Simulation Method ◽  
Test Results ◽  
Forward Flight ◽  
Time Stepping ◽  
Coaxial Rotor ◽  
Dual Time Stepping ◽  
Computational Fluid Dynamics Cfd ◽  
Nested Grid

In this paper, a computational fluid dynamics (CFD) simulation method based on the polyhedral nested grid is developed. By comparing the simulation and test results of the hovering flow field of the Caradonna–Tung rotor, the forward flight flow field of the AH-1G rotor, the interference flow field of the Robin rotor/fuselage, and the hovering and forward flight flow field of a coaxial rotor, it is proven that the method proposed in this paper can achieve high calculation accuracy under various working conditions. The dual time-stepping method is used for the transient simulation, and the Spalart–Allmaras (S-A) turbulence model, which is widely used in aviation, is adopted in the simulation.

scholarly journals Impulsive Loading Noise of a Lift-Offset Coaxial Rotor in High-Speed Forward Flight

AIAA Journal ◽  
2020 ◽  
Vol 58 (2) ◽  
pp. 687-701 ◽  
Author(s):  
Zhongqi Jia ◽  
Seongkyu Lee
Keyword(s):  
High Speed ◽  
Impulsive Loading ◽  
Forward Flight ◽  
Coaxial Rotor
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