Numerical simulation of falling objects settling and impacting submarine pipelines under the action of ocean currents
The dynamic boundary problem of falling objects in ocean currents is simulated by the sharp interface immersed boundary method.The settling motion of a falling object and its collision with a pipeline are solved by the finite element method based on the penalty function.The coupling solution of the falling object and ocean current is obtained by the partitioned coupling approach.The complete process of the falling object impacting the submarine pipeline under the action of ocean current is numerically simulated.The numerical results show that the flow velocity of the falling object is almost the same as that of the ocean current in free settling.The vertical velocity of falling objects with the same mass is almost the same under different current velocities.However,thrust occurs at lower mass and current velocity.The vertical drag coefficient of spherical objects is smaller than that of cubic objects,and the drag coefficient changes with the mass of objects.When the falling object approaches the submarine pipeline,the flow velocity decreases gradually,and the vertical velocity increases first and then decreases.The vertical velocity of heavy objects decreases more than that of low-mass objects.When the falling object hits the pipe,the impact velocity of the spherical falling object is larger than that of the cube.The impact velocity is larger than the free sedimentation velocity and the impact angle is smaller than the free sedimentation angle.The maximum stress and indentation are smaller than that without current action.The stress reduction range of spherical falling objects is 4.44％-16.71％,and the stress reduction range of cubic falling objects is 9.29％-12.14％.The dent reduction range of spherical falling objects is 4.17％-30.58％,and the dent reduction range of cubic falling objects is 10.41％-14.44％.Compared with past research,the method in this paper is more realistic,and the research results can provide a certain reference for the design of submarine pipeline engineering.
safety engineeringsubmarine pipelineimpactfluid-structure interactionimmersed boundary-finite element methodnumerical simulation
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NSTL
万方数据
维普
