Page 165 - Pipelines and Risers

Cross-flow direction (vertical plane).

- Combined In-line Fatigue

There are three sources of in-line fatigue:

0 in-line motion due to cyclic wave-induced oscillations, which may be simulated using a
Force Model;
in-line vibrations due to in-line vortex-induced resonance, which may be simulated using
an Amplitude Response Model;
0 in-line vibrations due to coupling from cross-flow vibrations.

Figure 10.1 Free-spanning Pipeline and its in-line and cross-flow directions.