DRAG FORCE AND RESISTANCE AROUND SINGLE GROYNE IN SUBMERGED FLOW CONDITION

Groynes have been used for the protection of banks, stabilization of bed morphology and also for establishing navigation channels. A typical Japanese river is characterized by large and sudden variations in discharge due to big amounts of rainfalls, so that the groynes are often in submerged condition. The present study focuses on flow pattern, drag force and resistance around a submerged single groyne. The PTV method and numerical shallow flow analysis are adopted to calculate velocities accurately. The flow pattern, drag force and flow resistance are estimated and compared at several points around the groyne. The relations between flow resistance and submerged flow depth are discussed in this study.