Summary: Coherent Structures in a Transitional Flow
around a Backward-Facing Step
Tino Weinkauf and Hans-Christian Hege, Zuse Institute
Bernd R. Noack, Michael Schlegel, and Andreas
Dillmann, Technical University Berlin
The transitional flow around a backward-facing step is
visualized using illuminated streamlines of a snapshot Fig.
1 . The flow separates at the corner of the step. The resulting
shear layer rolls up in two KelvinHelmholtz vortices. In the
downstream direction, the streamlines form bundles due to
secondary streamwise vorticity. The fluid experiences a small
backward flow in the upstream region below the shear layer.
The flow field is obtained from a large-eddy simulation by
Kaltenbach and Janke at a Reynolds number of ReH 3000
based on oncoming velocity and on step height. The corre-
sponding boundary conditions are described in Ref. 1.
The streamlines are illuminated in order to enhance the
three-dimensional perception of the scene. This highly inter-