Affiliation:
1. Fluid Mechanics Department, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
2. Department of Physics, Aerospace Engineering Division, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
Abstract
We analyze the incompressible flow past a square cylinder immersed in the wake of an upstream splitter plate, which separates two streams of different velocities, UT (top) and UB (bottom). The Reynolds number associated with the flow below the plate is kept constant at [Formula: see text], based on the square cylinder side D as characteristic length. The top-to-bottom flow dissymmetry is measured by the ratio [Formula: see text] between the Reynolds numbers above and below the plate. The equivalent bulk Reynolds taken as the mean between top and bottom changes with R in the range [Formula: see text]. A Hopf bifurcation occurs at [Formula: see text] ([Formula: see text]), which results in an asymmetric Kármán vortex street with vortices only showing on the high-velocity side of the wake. A spanwise modulational instability is responsible for the three-dimensionalization of the flow at [Formula: see text] ([Formula: see text]) with the associated wavelength of [Formula: see text]. For velocity ratios [Formula: see text], the flow becomes spatiotemporally chaotic. The migration of the mean stagnation and base pressure points on the front and rear surfaces of the cylinder as R is increased determine the boundary layer properties on the top and bottom surfaces and, with them, the shear layers that roll up into the formation of Kármán vortices, which in turn help to clarify the evolution of the lift and drag coefficients. The symmetries of the different solutions across the flow transition regime are imprinted on the top and bottom boundary layers and can, therefore, be analyzed from the time evolution and spanwise distribution of trailing edge boundary layer displacement thickness at the top and bottom rear corners.
Funder
Ministerio de Economía y Competitividad
Ministerio de Ciencia, Innovación y Universidades
Agència de Gestió d'Ajuts Universitaris i de Recerca
Red Española de Supercomputación
Subject
Condensed Matter Physics,Fluid Flow and Transfer Processes,Mechanics of Materials,Computational Mechanics,Mechanical Engineering
Cited by
5 articles.
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