General Nonlinear Analysis of Marine Risers

A new and practical method for the nonlinear analysis of marine risers excited by single wave and steady current is presented in this paper. The Nonlinear drag force is expressed by Fourier expansion up to any nth order to meet the desired accuracy. Applying the iterative-calculation procedure, all the Fourier coefficients could be obtained easily by the numerical integration. An application example is studied for demonstration. Comparisons of the riser responses calculated by the Fourier expansion, first-order Fourier expansion, and step-by-step integration are also included.