Three-dimensional Simulation Of Dynamics Response For The Flexible Riser Of Spar

The marine riser is an important component of an oil drilling and production system. It is essentially a slender, flexible pipe conveying fluid between the wellhead and a floating production system. The literature abounds with analysis methods for marine risers. At first, Dynamic response of the riser is stay in the static analysis which can get the stable profile and the tension. But it is not enough. Due to the change of the ocean environment at all the time, the riser operate an adaptable movement along with the environment interfere. This has created the need for reliable analysis methods that address the design problems associated with the riser's laying. Further, a lumped-mass formulation allows the flexibility of dealing with varying material properties and fluid loading along the riser's length. So this article uses Lumped Parameter Method to the Marine riser for stress analysis, and deduced the three-dimensional dynamic mathematical model.The analysis of the dynamic response characteristics about the common offshore platform which Focuses on the spar are given in Section 1. The static analysis of the underwater riser are introduced in Section 2. The auther derives the classical catenary equations. The wave force and the moment affect on the riser is derivated by the differential forms of the Morrison equation. The section 3 makes the model idealized which ignores the impact of torque. The wet weight, tension and damping force is went into details especially the formula of the moment force . The fourth section describes the method for solving ordinary differential equations, and highlights the 4th order Runge-Kutta method. The preliminary application of ODE solver group is also introduced. Section 5 and Section 6 is the conclusion and outlook studies. Appendix is written in the riser of a dynamic simulation program.MATLAB software is applied as an exploiting flat, where three dimension dynamic characteristic of cables is programmed to analyze. Simulating experimental data is compared with classic catenary equation and related literature. The dynamic response analysis of the riser is realized by the simulation system, by which the stable profile of riser in different ocean environment is received. According to the program to simulate the riser descending, and the result shows the current has visible effect which the larger velocity goes with the easier stability riser. When the riser with the platform to simple harmonic motion, the top tension reaches a certain value. These simulation results match the actual experience. All of these indicate the correctness of the simulation, which can provide the valuable reference data to early designing stage and have certain engineering appliance value.