Three Dimensional Flow Development in the Wake of Elongated Bluff Bodies
نویسندگان
چکیده
The results from Floquet stability analysis of the flow around nominally two-dimensional long plates with elliptical leading edges and blunt trailing edges are presented, elucidating the early stages of wake transition to turbulent flow. Three modes of instability are found: Mode A, Mode B and a period doubling mode. The first two of these also occur in wake transition for circular cylinders and square cross-sectioned cylinders. For sufficiently large aspect ratio, Mode B is found to be the dominant instability mode. This research indicates the generic turbulence transition scenario suggested for circular twodimensional bodies does not apply to all two-dimensional bluff bodies.
منابع مشابه
A Review of Recent Studies on Simulations for Flow around High-Speed Trains
Fluid flow around bluff bodies occurs in numerous fields of science and engineering, such as flows pass vehicles, cables, towers and bridges. These flows have been studied experimentally and numerically for the last several decades. The investigation of flow around high-speed trains is an important application of bluff bodies. Fluid flow, aerodynamic forces and moments, separation and wake regi...
متن کاملElimination of vortex streets in bluff-body flows.
We present an effective technique for suppressing the vortex-induced vibrations of bluff bodies by eliminating the von Kármán street formed in their wake. Specifically, we find that small amounts of combined windward suction and leeward blowing around the body modify the wake instability and lead to suppression of the fluctuating lift force. Three-dimensional simulations and stability analysis ...
متن کاملStochastic modelling and feedback control of bistability in a turbulent bluff body wake
A specific feature of three-dimensional bluff body wakes, flow bistability, is a subject of particular recent interest. This feature consists of a random flipping of the wake between two asymmetric configurations and is believed to contribute to the pressure drag of many bluff bodies. In this study we apply the modelling approach recently suggested for axisymmetric bodies by Rigas et al. (J. Fl...
متن کاملThe structure of primary instability modes in the steady wake and separation bubble of a square cylinder
Flows past symmetric two-dimensional bluff bodies such as the circular cylinder, the square cylinder, and the normal flat plate produce large separation bubbles which (in the steady restriction) may become very elongated at comparatively low Reynolds numbers. The present work focuses on the steady/symmetric wake of a square cylinder at Re ≤ 300, which loses stability to anti-symmetric two-dimen...
متن کامل