THE CHARACTERISTICS OF HYDRODYNAMIC FORCES ON EMERGENT CYLINDERS IN OPEN CHANNEL FLOW

The evaluation of the hydrodynamic forces acting on vegetation and structures in rivers is important for river management. In this study, we focused on undisturbed flows to discuss (i) the changes in pressure and water-surface distributions induced by installing emergent cylinders in open channel flows and (ii) the hydrodynamic force acting on them. We proposed an evaluation method of the hydrodynamic force by clarifying the force being composed of four forces whose physical origins are different, i.e., the buoyant force in the flow direction, the force in the free stream flow, the force due to water surface deformation, and the force exerted by the pressure gradient. Finally, we examined the validity of the evaluation method by applying it to a water-surface profile calculation.