Authors: Tanja SiegmannHegerfeld Stefan Albensoeder Hendrik C Kuhlmann
Publish Date: 2008/04/19
Volume: 45, Issue: 5, Pages: 781-796
Abstract
Two and threedimensional flows in nearly cuboidal cavities are investigated experimentally A tight cavity is formed in the gap between two long and parallel cylinders of large radii by adding rigid top bottom and end walls The crosssection perpendicular to the axes of the cylinders is nearly rectangular with aspect ratio Γ The axial aspect ratio Λ 10 is large to suppress endwall effects The fluid motion is driven by independent and steady rotation of the cylinders about their axes which defines two Reynolds numbers Re 12 Stability boundaries of the nearly twodimensional steady flow have been determined as functions of Re 12 for Γ = 076 and Γ = 1 Up to six different threedimensional supercritical modes have been identified The critical thresholds for the onset of most of the threedimensional modes three of which have been observed for the first time agree well with corresponding linearstability calculations Particular attention is paid to the flow for Γ = 1 under symmetric and parallel wall motion In that case the basic flow consists of two mirror symmetric counterrotating parallel vortices They become modulated in spanwise direction as the driving increases Detailed LDV measurements of the supercritical threedimensional velocity field and the bifurcation show an excellent agreement with numerical simulations
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