ACTA AERONAUTICAET ASTRONAUTICA SINICA >
Lift enhancement mechanism for local oscillation of airfoil surface at low Reynolds number
Received date: 2014-12-23
Revised date: 2015-04-01
Online published: 2015-04-15
Supported by
National Natural Science Foundation of China (11402212);The Fundamental Research Funds for the Central Universities (3102014JCQ01002)
Aerodynamic performance and the related flow patterns are studied for low Reynolds number flow with local oscillation of airfoil surface using computational fluicl dynamics (CFD) method. The model of local oscillation of airfoil surface is established and flow around the airfoil under the oscillation is simulated by arbitrary Lagrangian Eulerian-characteristic based split (ALE-CBS) algorithm. The effect of the local oscillation on flow evolution is highlighted to reveal the mechanism for lift enhancement. The results show that the local deformation of the surface reduces the suction pressure on the leading edge efficiently. Moreover, the crucial factors for lift enhancement of local oscillation are the distance between the vortices in the flow separation zone and the relationship between the oscillating frequencies and frequencies of vortex formation. The moving separation bubbles can transfer more energy from the main stream to keep a lower pressure on the upper surface so that the lift of the airfoil is improved effectively, as the primary frequency of flow equals the oscillating frequency and the second order frequency of the flow is twice of the first one, i.e. frequency lock-in occurs.
KANG Wei , LIU Lei , XU Min , LEI Pengfei , ZHANG Jiazhong . Lift enhancement mechanism for local oscillation of airfoil surface at low Reynolds number[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2015 , 36(11) : 3557 -3566 . DOI: 10.7527/S1000-6893.2015.0094
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