Hydrodynamic characteristics of lock-exchange flow in curve channels in the presence of blocks

Gravity current is the flow of fluid through another fluid of varying density. This flow often occurs in nature. For optimal management of water resource quality, it is necessary to know and study the gravity current. Naturally, many streams have a meandering path. There are also many blocks in different shapes (both natural and artificial). Therefore, in the present study, to control a lock-exchange gravity current, a triangular, rectangular, or trapezoidal rigid barrier was placed inside a curved channel with a curvature of 120 degrees and a radius (R) of one meter. Simulations were performed using the OpenFoam open-source software and the realizable k-ɛ turbulence model. The Reynolds number was 19700 in all of them. According to previous studies, in a block-free channel, the most secondary current occurs in the middle of the curve. In this study, to control the secondary current, the blocks were placed at 60 degrees of the curve. With an impediment, the secondary current was visible in the body and tail of the current but did not occur in the current head. The obstacle affected the pattern of the secondary currents so that the pattern was different around the block from the other locations. The barrier also reduced the spanwise velocity of the flow body. The concentration was maximum at the head of the stream, indicating that the barrier could affect the concentration along the stream so that the maximum concentration was behind the block. The current head was also affected by the block, as it did not advance for a moment on the inner bank; at these moments, the outer bank surpassed the inner bank.