Numerical Modeling of Scour Pattern Downstream of Combined Flow over Weirs and Under the Gates by Flow3D

By combining weirs and gates the problems of sedimentation and floating materials upstream the weir and gate structure can be resolved. In combined structures a new hydraulic condition is created which is differing from hydraulic condition in weir and gate only structures. Due to jet flow passing through or under structure، the scour hole is formed downstream of structures that’s may endanger the stability of the structure. So determination of scour hole characteristics is attracted by researchers. The object of this study is numerical modeling of scour pattern downstream of combined flow over weir and under the gate by Flow3D software. For modeling the turbulence، RNG k-، k- and LES were used. Flow3D is a high accurate model in computational fluid dynamics for simulation of problem with complex geometry on wide limits of fluid flows in open channel hydraulic. By applying VOF method، a series of simulation scour pattern downstream of weir - gate structure were performed and results were compared by some experimental data. The results show that Flow3D with LES turbulent model can be used with high accuracy (with R2=0. 96، RMSE=0. 0117) to simulation of scour pattern and water surface profile in weir - gate structure.