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Experimental and numerical analysis of the bi-stable turbulent wake of a rectangular flat-backed bluff body.
- Source :
-
Physics of Fluids . Oct2020, Vol. 32 Issue 10, p1-20. 20p. - Publication Year :
- 2020
-
Abstract
- The wake dynamics of a rectangular flat-backed bluff body is studied using both the wind tunnel experiment and Improved Delayed Detached Eddy Simulation (IDDES) at Re = 9.2 × 104. Both approaches are systematically investigated in order to provide a quantitative comparison. The wake barycenter deficit and base pressure gradient dynamics are first investigated to characterize the wake states. Second, the known global dynamics such as long-term bi-stability, vortex shedding, and wake pumping are analyzed using proper orthogonal decomposition. It is found that the wake dynamics is globally well captured by the IDDES, but with a more intense activity due to the absence of the fore-body separations observed in the experiment. The coupling of these global dynamics is explored by utilizing low-order modeling in cross planes and elaborating the evolution of the three-dimensional (3D) instantaneous wake flow from IDDES. The shedding of a large-scale hairpin vortex from the horizontal shear layer is closely associated with the pumping motion during wake switchings or switching attempts. A concept model is proposed for 3D bi-stable wake topology, which attempts to elucidate both asymmetric and symmetric wake configurations. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10706631
- Volume :
- 32
- Issue :
- 10
- Database :
- Academic Search Index
- Journal :
- Physics of Fluids
- Publication Type :
- Academic Journal
- Accession number :
- 146790451
- Full Text :
- https://doi.org/10.1063/5.0019794