LAUSR

Abstract In this paper, the influence of the damping matrix and mud discharge on the recoil response of deepwater drilling riser after emergency disconnection is studied based on our published study. Mathematically, the deepwater drilling riser is discretized into a mass-spring-damping system with three degrees of freedom (DOF). The governing equation is solved by the principal coordinates analysis method (Method A) and the complex modal analysis method (Method B), respectively. Firstly, the mathematical expression of the frictional resistance acting on the riser during mud discharge is obtained by curve fitting. Then, the detailed solving process and the difference of the results calculated by the two solving methods are shown. The influence of the non-diagonal elements in the damping matrix on the recoil response is studied. In addition, the effect of the frictional resistance of mud discharge on the recoil characteristics is assessed. Finally, conclusions are drawn based on the analysis.