Experimental study on a new riser in large flume under the influence of wave and current

The traditional riser system needs to recover all the risers when typhoon comes, which often takes a long time and high risk. In recent years, a new type of anti-typhoon riser system emerged, which can realize the emergency separation of the upper offshore platform and the lower riser system near the water surface, and the remaining riser can stand in the deep water freely through the net buoyancy provided by the buoy. In order to verify the feasibility of the new anti-typhoon riser system, the vortex induced response of the riser under the combined action of wave and current is studied by physical model test in large flume with geometric scale of 1:21 under three different net buoyancy conditions; The results show that the net buoyancy of the buoy has a great influence on the natural frequency and motion response of the new riser. Under the combined wave current condition, the wave restrains the vortex induced motion of the riser in a certain extent and reduces its overall offset.