Experimental and 3-D Numerical Investigation on Separation Zones of Gravel Dunes

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

کلیدواژه ها:

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