An Analysis of Flowing Pattern around T-shaped Spur Dike at 90° Arc, Based on Fluent and Flow-3D Models

In this paper the analysis of scouring has been analyzed، which usually takes place in river bends at high speeds. River’s spur dikes are considered as important organizing structures of rivers. Spur dikes are cross-over structures which expand from river bank to flowing axis and deflect or direct flow to river’s central axis. The spur dikes are formed individually or in subsequent series in one or both sides of the river. In this paper، the analysis of the flow speed and scouring around T-shaped spur dike at 90 degrees arc، have been considered. A three-phase flow simulation of air، water and sediment was used based on the VOF model via fluent and flow-3D software’s. Using these software’s، scouring phenomenon was examined for three different volume rates. Observations suggested the spur dike affected topography of the arc bed due to the flow pattern of the secondary flow and formation of another secondary flow in the opposite direction of the main secondary flow. Results clearly showed that as the volume rate goes up، the scour rate in the external arc and sedimentation rate in internal arc increases. Results also revealed that in a no-spur dike in the arc، scouring rate was five times more than when there was a spur dike.