Three-Dimensional Transition in the Wake of an Ellipse

The transition to three-dimensional flow from the nominally two-dimensional Kármán vortex street in the wake of bluff bod-ies is a problem of fundamental importance as it marks the first step on the path towards fully developed turbulence. Here, this transition is studied in the wake of an elliptical cross-section us-ing Floquet stability analysis. A number of modes of instability are identified as a function of the aspect ratio of the ellipse. Three-dimensional simulations confirm the importance of the identified instability modes