ARTEMIS MOTAMEDI - PhD student Dept of Water Engineering, Isfahan Univ of Technology, Isfahan
HOSSEIN AFZALIMEHR - Associate Professor Deptof Water Engineering, Isfahan Univof Technology, Isfahan
MAJID GALOIE - PhD student Graz University of Technology (TUGraz-Austria), Institute of Hydraulic Engineering and Water Resources Management
CLEMENS DORFMANN - PhD student Graz University of Technology (TUGraz-Austria), Institute of Hydraulic Engineering and Water Resources Management

On the basis of laboratory experiments, this paper presents the effect of different dune dimensions on flow separation. The present research assesses the quality of Reynolds- Averaged Navier-Stokes turbulence model for predicting the flow over twodimensional dunes. Three different dunes were developed with two lee-slope angles of 8° (Δ= 4&6 cm) and 38° (Δ= 8 cm).The length of the simulated separation zone was compared with experimental data. It is found that the numerical model provides a good overall consistency with the ADV measurements. Also the separation zone has a strong relation with the lee angle. At lee angles less than 10°, the shape of the crest or dune height has no effective impact on flow separation

Dune, Lee Angle, 3-D Numerical Modelling, Separation Zone, Reattachment Point