Calculation of optimal hydraulic cross section for U-shape canal
zhang zhi-chang1; li yin-cai2; liu ya-fei1; lu jun3; zhang xue-zheng4 (1. xi an university of technology; shaanxi xi an 710048; china; 2. administrayion division of hanyan canal; ningxia yongning 750100; china; 3. ankang institute of survey and desig