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Locked-on vortex shedding modes from a rotationally oscillating circular cylinder
, Qasem Al-Mdallal M., Rajendra Ray K.
Published in
2017
Volume: 146
   
Pages: 324 - 338
Abstract
Numerical simulations of unsteady two-dimensional flow around a rotationally oscillating circular cylinder, placed in a uniform cross flow of a constant property Newtonian fluid, are performed at a fixed Reynolds number of 200. The investigation is based on the solutions of stream function-vorticity formulation of Navier-Stokes equations on non-uniform polar grids using a higher order compact (HOC) formulation. The flow field is mainly influenced by Reynolds number, Re, maximum angular velocity of the cylinder, $\alpha$m and the frequency ratio, f/f0, which represents the ratio between the frequency of oscillation, f and the natural vortex shedding frequency, f0. The ranges considered for these parameters are 0.5⩽$\alpha$m⩽6.0 and 0.5⩽f/f0⩽3.0. The resulting vortex formation modes and lock-on phenomena behind the cylinder as well as the fluid forces acting on the cylinder are analyzed. Occurrence of new multiple lock-on regions is demonstrated in detail by the variation of f and $\alpha$m. The instances of high drag reduction at high values of $\alpha$m are confirmed. Comparisons with previous numerical and experimental results verify the accuracy and validity of the present study.
About the journal
JournalOcean Engineering
ISSN00298018