埋设海底电缆水力移动射流冲刷沙床试验及数值模拟研究OA

The hydraulic mobile jet flushing sand bed experiments and FLOW-3D numerical simulations were conducted to study the sediment movement in submarine cable burial.The double-nested regional mesh refine-ment technique was employed in the numerical model.Results show that the scour pit development generally goes through three stages:sand-breaking turbulence under the action of high-speed jet flow,sidewall shaping,and equilibrium state of suspended sediment deposition.Under the mobile jet of the trenching machine,back-filling occurs significantly at the rear of the moving path,and the relative backfilling degree increases with the translational speed and jet flow velocity.Moving the jet will reduce the depth and width of the scour pit,and the pit surface tends to be elliptical.The key sand parameters affecting the section results of the numerical model were determined:The critical Shields number,R-Z coefficient,and repose angle of s are the key pa-rameters of sediment affecting the section of scour pit in the numerical model.After non-dimensional analysis,the flatness change rate e of scour pit and Froude number Fr of jet flow at the nozzle exit can be linearly corre-lated.This research provides theoretical basis and technical support for evaluating the protection effect based on sand bed morphology changes during submarine cable burial.