ACTA AERONAUTICAET ASTRONAUTICA SINICA >
Unsteady flow interaction mechanism of coaxial rigid rotors in hover
Received date: 2015-01-04
Revised date: 2015-04-15
Online published: 2015-04-21
Supported by
National Natural Science Foundation of China(11272150);Project Funded by the Priority Academic Development of Jiangsu Higher Education Institutions
A computational fluid dynamics(CFD) method based on moving-embedded grid technique is established to simulate the unsteady flow field of the coaxial rigid rotor in hover. In this solver, based on the highly-efficient moving-embedded grid technology, the simulation method is developed by solving the compressible Reynolds-averaged Navier-Stokes(RANS) equations with Baldwin-Lomax turbulence model and a dual-time method. Based upon the validation of the present CFD method, during the process of blade-vortex interaction in hover, close vortex-surface interactions and impingement phenomenon have been observed; at the same time, the interaction process among the vortexes shed from the upper blades and lower blades has been captured obviously, as a result, the evolution laws of position and strength of blade-tip vortex shed from different blades are obtained in detail. Furthermore, the periodic unsteady characteristics and variation trend of the aerodynamic forces of the upper rotor and lower rotor have been analyzed. The simulation results demonstrate that the upper blade vortices can impinge upon the lower blade, which causes the thrust loss of lower blade; the strength and positions of the vortexes shed from upper blades and lower blades could change due to the interaction; the forces on both the upper and lower rotors increase as the blades approach, then decrease and increase again as they move away.
ZHU Zheng , ZHAO Qijun , LI Peng . Unsteady flow interaction mechanism of coaxial rigid rotors in hover[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2016 , 37(2) : 568 -578 . DOI: 10.7527/S1000-6893.2015.0106
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