Direct numerical simulation of turbulent flow past a T-beam

Abstract

The turbulent near-wake behind a T-beam has been investigated by means of direct numerical simulations (DNS) at Reynolds number 1000. The oncoming flow was perpendicular to the leg of the T-beam and the presence of the flow-parallel part of the T-beam made the wake distinctly different from that of a normal flat plate. The flow separated from the free end of the leg and at the leading edge of the flow-parallel plate. The return flow was fed by one of the two major recirculation bubbles in the near-wake. The presence of the flow-parallel plate inevitably broke the symmetry of the wake and this symmetry breaking showed up in both instantaneous flow field and time-averaged statistics. The flow in the lee of the free end of the normal plate turned out to be more energetic than the flow behind the trailing edge of the flow-parallel plate. The primary shedding frequency was the same in both halves of the wake, but the Strouhal number became distinctly lower than in the wake of a normal flat plate at the same Reynolds number.

Keywords:

• T-beam
• asymmetric vortex shedding
• free shear layers
• turbulence
• wakes

Acknowledgements

The authors thankfully acknowledge the constructive comments made by the reviewers, which helped us to improve the final version of this manuscript. We are also grateful to the Research Council of Norway (Program for Supercomputing) for a grant of computing time.