Coherent structures in a transitional flow around a backward-facing step

The transitional flow around a backward-facing step visualized using illuminated streamlines of a snapshot ~Fig. 1!. The flow separates at the corner of the step. The resu shear layer rolls up in two Kelvin–Helmholtz vortices. In th downstream direction, the streamlines form bundles due secondary streamwise vorticity. The fluid experiences a sm backward flow in the upstream region below the shear la The flow field is obtained from a large-eddy simulation Kaltenbach and Janke at a Reynolds number of Re H53000 based on oncoming velocity and on step height. The co sponding boundary conditions are described in Ref. 1. The streamlines are illuminated in order to enhance