Numerical Design and Preliminary Evaluation of a U-Shaped Hydraulic Flume for Flood Early Warning Applications

Universitas 17 Agustus 1945 Surabaya, Study Program of Civil Engineering, PO Box 60118, Indonesia

^* Corresponding author: andipatriadi@untag-sby.ac.id

Abstract

The present study introduces the design and preliminary evaluation of a U-shaped hydraulic flume aimed at supporting flood early warning systems. Numerical simulations were employed to investigate flow characteristics under subcritical conditions, both with and without spur dike structures. The baseline scenario with an inlet velocity of 0.463 m/s demonstrated stable subcritical flow upstream and supercritical transition downstream, with velocity concentrated along the outer bank. The addition of two spur dikes successfully diverted the main current toward the channel centerline, reducing outer-bank velocity and mitigating erosion risk. However, high turbulence and concentrated velocity at the spur dike tips revealed the potential for localized scouring. Furthermore, the spur dikes caused a reduction in upstream water surface elevation, suggesting a secondary benefit in lowering flood levels entering the bend. These findings highlight the potential dual function of spur dikes in erosion control and flood regulation. Nonetheless, the study remains limited to numerical analysis, with physical validation required in future research to enhance the robustness of the results.