Longitudinal Resonant Behavior of Very Deep Water Risers

This paper is concerned with the problem of longitudinal resonant vibration of a 3000-m-long disconnected riser. Theoretical investigations of natural frequencies and induced displacements and dynamic tensions are presented, as well as practical investigations of riser longitudinal hydrodynamic damping and of short period heave excitation, likely to be communicated to such a riser, by a typical drillship. Analytical expressions, useful for describing and understanding resonant behavior, are developed in the Appendix.