Thorough analysis of vortical structures in the flow around a yawed bluff body

• Published in: Journal of turbulence 2008-01, Vol.9 (9), p.15-15
• Main Authors: Gohlke, M., Beaudoin, J. F., Amielh, M., Anselmet, F.
• Format: Article
• Language: English
• Subjects: bluff-body aerodynamics; cross-wind; vortex analysis; vortex detection
• ISSN: 1468-5248; 1468-5248
• DOI: 10.1080/14685240802010657

In the present study numerical investigations are used as a complementary approach to analyse large coherent structures in the flow around a bluff-body under cross-wind. The results from the numerical simulation are validated through wind-tunnel experiments and used to analyse unresolved observations from these experimental investigations. This underlines the duality of these two approaches in the analysis of the aerodynamics of a bluff-body. Vortical structures in a three-dimensional, asymmetric and turbulent wake are detected through the use of different vortex detection schemes (vorticity, Q, λ 2 and Γ 3 ), permitting to isolate flow structures. The vortex properties of two main lateral vortices are described and discussed on the basis of envelopes detected by the λ 2 and the Γ 3 criterion. Although the flow is highly three-dimensional and complex, the vortex properties are quite simple and show mechanisms like vortex stretching and bursting. These two criteria lead qualitatively to the same results; quantitative differences are due to the envelope diameter and are therefore observed only on integral flow quantities.