Investigation of Flow Dynamics in a Flume with Connected and Spaced Levee–Moat System Using CFD

Abstract

Applying efficient energy dissipation and flow control systems has been emphasized by the rising occurrence of coastal flooding and river floods. This study numerically examines the hydrodynamic performance of levee-moat systems (in ANSYS Fluent) with respect to the use of computational fluid dynamics (CFD). Two model cases were analyzed: a directly connected levee-moat (DC_LM), and spaced apart levee-moat (SA_LM). The study has used the volume-of-fluid method and RNG- k–ε type of turbulence model to calculate the interaction at the free surface. These values demonstrated a range of velocity variation between 0m/s at the levees and moat base to 1.4 m/s on the levee slope in DC_LM and 1.63 m/s in SA_LM in the free-flow regions with strong velocity gradient and recirculation zones. The energy loss obtained was 19% for DC_LM and 17% for SA_LM, showing greater energy dissipation in the direct connection as a result of stronger turbulence due to strong hydraulic jump. The distance between the moat and the levee leads to more chances of scouring and also increases the chances of structural damage of the moat. These findings underscore the significant role of structural geometry and spacing on hydraulic energy control, which can be of useful information in the design of flood and tsunami mitigation measures.