The Effect of the Seabed Proximity on the Hydrodynamic Forces of the Piggyback Pipeline Under Wave Action

This paper presents experimental results for the hydrodynamic forces of the piggyback pipeline in the proximity of the seabed under regular and irregular wave action. Non-dimensional force coefficients for drag, inertia and lift are obtained based on Morison equation. The effect of the gap ratio e / D between the large pipeline and the seabed on the force coefficients of the piggyback pipeline is studied experimentally. The results indicate that the force coefficients initially decrease and then remain constant beyond e / D = 0.5.