Complex flexible riser Download the model: complex_flexible_riser.stask Figure 1. Figure: Complex flexible riser — SIMA model view 1. Description This example demonstrates a complex flexible riser configuration in RIFLEX, combining several advanced modelling features in a single model. The riser runs from a hang-off on a floating vessel down to a seabed anchor in a water depth of 90.5 m, draping over a tethered mid-water arch (MWA) that shapes it into a steep-wave configuration. The model brings together the following features: Bending stiffener at the hang-off, modelled as a tapered sequence of cross sections with decreasing bending stiffness. Mid-water arch modelled as a nodal body providing buoyancy, held down by tethers and branch lines. Elastic contact against the arch’s elastic contact surface, so the riser is free to slide over the arch. Tethers anchoring the mid-water arch to the seabed. Smeared buoyancy and smeared clump-weight sections, giving distributed net buoyancy / net weight along parts of the riser. Internal fluids (oil and water) with inlet pressure, see internal fluid type. The riser is modelled with axisymmetric cross sections, the appropriate type for flexible pipe. The static analysis builds the equilibrium configuration in a load sequence (geometry, arch roll, vessel displacement, current, boundary change); the dynamic analysis is a short irregular time-domain simulation driven by the vessel motions and the wave/current environment. The simulation length is controlled by the simulationLength variable (default 60 s). Figure 2. Figure: Complex flexible riser — slender system sketch