Inscrição na biblioteca: Guest
Third Symposium on Turbulence and Shear Flow Phenomena
June, 25-27, 2003, International Center, Sendai, Japan

DOI: 10.1615/TSFP3

FLOW PAST AN OSCILLATING BI-CONVEX AEROFOIL

pages 1139-1144
DOI: 10.1615/TSFP3.1900
Get accessGet access

RESUMO

This preliminary study aims to investigate the flow structure of an impulsively started bi-convex aerofoil, both at fixed incidences as well as in oscillation, using a digital cross correlation particle image velocimetry (PIV) technique. The experiments are conducted in a recirculating, piston (water) tunnel and the angular amplitude as well as the reduced frequency are varied for a given Reynolds number and linear acceleration.
The results of the experiments show that for the static case, an increase in the angle of attack intensifies the instabilities within the flow whilst for the oscillating cases, the reduced frequency, rather than the angular amplitude, is the key parameter which influences the fundamental characteristics of the flow.
The lower reduced frequency cases display characteristics that are remarkedly similar to that of the static stall cases, with the main distinction being a chronological delay in the flow evolution characteristics that exists between the former and the latter at any particular angle of attack.
The higher reduced frequency cases, on the contrary, are set apart from the other cases in both leading edge and wake development. The leading edge activity seems to be out of phase with what would normally be predicted in a quasi-steady condition whilst the wake vortex generation is predominantly due to the rotation of the aerofoil rather than the effect of the translating flow, as in the lower reduced frequency cases.

Portal Digital Begell Biblioteca digital da Begell eBooks Diários Referências e Anais Coleções de pesquisa Políticas de preços e assinaturas Begell House Contato Language English 中文 Русский Português German French Spain