Numerical investigation of flow characteristics horizontal sharp edge triangular weir with vertex at downstream

One of these types of weir is the sharp edges overflow, which is widely used due to the current flow pattern and ease of flow pass. In the present study, the flow characteristics of the proposed horizontal sharp edge triangular overflow with different angles of 30, 60, 90, 120, 150 and 180 degrees at downstream are simulated for 10 different discharges using the FLOW-3D numerical model. In this regard, after validation of the amount of the flow depth over the weir with valid experimental results, parameters of the discharge coefficient, pressure profile, velocity in transverse section and flow pattern have been calculated and analyzed. The results indicated the high accuracy of RNG turbulence model compared with other turbulence models with correlation coefficient R2 = 0.9996. Other results showed that discharge coefficient of proposed weir increases with 6% in compared with experimental weir model (with vertex at upstream). Weir with 150-degree angle has the highest increment of discharge coefficient with about 8.5%. As the angle rises from 30 to 150 degrees, the minimum pressure range progresses from the tip of the weir and goes downwards. The maximum amount of pressure in the downstream of overflow was observed for weir with 120-degree angle with a value of 1100 Pascal. The minimum pressure of 10 pascal was obtained in a small range of 150-degree weir. As the flow approach to tip of the overflow, the flow passing from the side and tip of the overflow and has high velocity values. The maximum longitudinal velocity was observed with a value of 1.53 meter on second in a 90-degree overflow.