URANS and DES simulation of flow around bridge sections

Kurzfassung

This paper deals with the numerical simulation of the flow around three different two-dimensional bluff bodies: a 1:1 square cylinder, a 1:5 rectangular cylinder and a realistic bridge section. The Unsteady Reynolds-Averaged Navier-Stokes (URANS) and the Detached-Eddy Simulation (DES) techniques are employed. In the process the influence of various modelling parameters, such as turbulence modelling, and flow parameters, such as Reynolds number and incidence angle, is investigated. Validation of computed results with the experimental data shows that the URANS-based computational approach is well capable of predicting the basic unsteady flow phenomena in the considered cases. The preliminary DES results enable a better insight in the flow physics while, at the same time, confirming the much less expensive URANS predictions. In addition, it is shown that the sharpness of section corners plays a key role in the development of the flow around typical bridge deck profiles, strongly affecting the Strouhal number and global aerodynamic coefficients.