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Experiments on the transition to time‐dependence in highly strained vortex flow inside a rectangular cavity
Author(s) -
Kuhlmann H. C.,
Blohm C.,
Albensoeder S.,
Rath H. J.
Publication year - 2002
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/1617-7061(200203)1:1<288::aid-pamm288>3.0.co;2-k
Subject(s) - reynolds number , flow (mathematics) , vortex , mechanics , instability , wavelength , laser doppler velocimetry , optics , physics , materials science , aspect ratio (aeronautics) , turbulence , optoelectronics , blood flow , medicine
The flows in a two‐sided lid‐driven cavity with a cross‐sectional aspect ratio Γ = 1.96 is experimentally investigated by laser‐Doppler anemometry and by hot‐film measurements. When the two facing walls move in opposite directions, a robust three‐dimensional flow consisting of four cells arises for Reynolds numbers Re ≥ 275 as a result of the elliptic instability. The flow within these steady cells is measured to high precision. For Re > 825 the four cell flow becomes oscillatory. The oscillations are due to a standing wave with the same wavelength as the underlying cellular flow.