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Film flow over strongly undulated bottom profiles at low Reynolds numbers – Experimental study
Author(s) -
Wierschem Andreas,
Scholle Markus,
Aksel Nuri
Publication year - 2003
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.200310153
Subject(s) - reynolds number , vortex , mechanics , flow (mathematics) , newtonian fluid , hele shaw flow , particle image velocimetry , particle (ecology) , physics , materials science , geology , turbulence , oceanography
We study gravity driven films of a Newtonian fluid flowing down sinusoidal bottom profiles. We give experimental evidence of vortices in the film flow under creeping flow conditions down to Reynolds numbers of the order of 10 –5 . The vortices are created in the valleys of the undulated bottom profile. They are visualized employing a particle image velocimeter with fluorescent tracers. It turns out that the vortices are generated beyond a critical film thickness.