Modelling of subcritical free-surface flow over an inclined backward-facing step in a water channel

¹ Institute of Thermomechanics AS CR, v.v.i., Dolejškova 1402/5, 182 00 Praha 8
prihoda@it.cas.cz
² Institute of Hydraulic Structures, Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00 Brno
Sulc.J@fce.vutbr.cz, Zubik.P@fce.vutbr.cz
³ SIGMA – Research and Development Institute, Jana Sigmunda 79, 783 50 Lutín
milan.sedlar@sigma-vvu.cz

Abstract

The contribution deals with the experimental and numerical modelling of subcritical turbulent flow in an open channel with an inclined backward-facing step. The step with the inclination angle α = 20° was placed in the water channel of the cross-section 200×200 mm. Experiments were carried out by means of the PIV and LDA measuring techniques. Numerical simulations were executed by means of the commercial software ANSYS CFX 12.0. Numerical results obtained for twoequation models and EARSM turbulence model completed by transport equations for turbulent energy and specific dissipation rate were compared with experimental data. The modelling was concentrated particularly on the development of the flow separation and on the corresponding changes of free surface.