TI - Effect of pier-collar system on flow characteristics of composite hydraulic structure AU - QASIM, R.M. AU - AL-ASADI, K. AU - ABDULHUSSEIN, I.A. AU - MAATOOQ, Q.A. SO - Sigma Journal of Engineering and Natural Sciences 2025;43:2066-2083. DO - 10.14744/sigma.2025.1911