Numerical Study of the Effects of Inlet Geometry on the Performance of the Sediment Bypass Tunnel using SSIIM Numerical Model

Sediment Bypass Tunnels (SBTs) are deviant channels that convey the current containing sediments from the upstream to the downstream of the reservoir. This study investigates the effect of hydraulic and geometry parameters such as discharge, flow depth and deviated channel width on the deviating of the flow and sediment to the SBTs. In addition, the effects of the submerged plates with angels ۳۰o, ۴۵o, and ۶۰o on the sediment transport to the ۹۰-degree deviated channel (SBTs) examined. The laboratory experiments conducted in the flume with ۱۰.۰ m long, ۰.۶۰ m width and ۰.۷۵ m height. Moreover, the SSIIM model used to simulate flow and sediment. The results revealed that the ۳۳% reduction of diversion channel width would lead to an ۸.۵% reduction of the deviated flow to the deviated channel. The maximum performance of deviated channel was obtained when the Froude number decreased and the flow depth increased. In terms of the angle of submerged plates, it can be observed that increasing the Froude number by ۰.۳ results in a ۲۲.۲% decrease in the channel deviated discharge and a ۵۳.۳% decrease in the channel deviated sediment. By reducing the Froude number of the flow and the depth along with using submerged plates at an angle of ۳۰ degrees, the optimal diversion option can be provided. The comparison results of the numerical simulation of the SSIIM model with experiment data indicated that it simulated deviated flow and sediment to the SBTs with the correlation coefficient more than ۰.۹۵.

Keywords:

Deviated channel , Sediment Transport , Deviated flow , Secondary flow , SSIIM numerical model