Stability analysis of the elliptic cylinder wake

Justin Scott Leontini, David Lo Jacono, Mark Christopher Thompson

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22 Citations (Scopus)

Abstract

This paper presents the results of numerical stability analysis of the wake of an
elliptical cylinder. Aspect ratios where the ellipse is longer in the streamwise direction than in the transverse direction are considered. The focus is on the dependence on the aspect ratio of the ellipse of the various bifurcations to three-dimensional flow from the two-dimensional Kármán vortex street. It is shown that the three modes present in the wake of a circular cylinder (modes A, B and QP) are present in the ellipse wake, and that in general they are all stabilized by increasing the aspect ratio of the ellipse. Two new pertinent modes are found: one long-wavelength mode with similarities to mode A, and a second that is only unstable for aspect ratios greater than approximately 1.75, which has similar spatiotemporal symmetries to mode B but
has a distinct spatial structure. Results from fully three-dimensional simulations are
also presented confirming the existence and growth of these two new modes in the
saturated wakes.
Original languageEnglish
Pages (from-to)302 - 321
Number of pages20
JournalJournal of Fluid Mechanics
Volume763
DOIs
Publication statusPublished - 2015

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