The hydraulic radius for flow in a rectangular duct of cross-sectional dimension H, W is___________________? March 10, 2019 – by admin The hydraulic radius for flow in a rectangular duct of cross-sectional dimension H, W is___________________? A. √(HW/π)B. HW/2 (H + W)2 C. HW/4 (H + W)2 D. 2HW/(H + W)