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The excitation mechanism of a shear stress induced rotary wave
Author(s) -
Steinrück Herbert,
Gusner Lorenz
Publication year - 2016
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201610295
Subject(s) - froude number , inviscid flow , mechanics , angular velocity , shear stress , free surface , flow (mathematics) , ekman number , physics , shear flow , classical mechanics
The free surface flow in a vertical, cylindrical, rotating container will be considered when axis‐symmetric angular and radial shear stress distributions are applied on the free surface. It is well known that in the inviscid case a rotary wave which can be described by a flow potential exists. We want to determine the stability limit of the axis‐symmetric base state with respect to the rotary wave for small Ekman and Froude numbers. Under the above assumption, the critical flow conditions can be determined analytically. The results can be verified experimentally using a vertical, cylindrical container partially filled with water where the top lid rotates with a given angular velocity. Thus, the induced air flow will exert shear stresses in the angular and radial direction onto the water surface. Above a certain threshold, rotary waves can be observed. (© 2016 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)