Pipe-soil interaction: An evaluation of a numerical model

The investigation of the evolution of the pipe/sea-bottom configuration has a large relevance for pipeline design as the occurrence and persistence for a certain period of a free-span causes the accumulation of fatigue on the pipeline which can lead to unacceptable damage. Of great importance is, therefore, the possibility of accurately predicting both generation and evolution of dangerous scour-induced free-spans. The onset of scouring is intimately connected with the dynamics of the bottom boundary layer and with the localized sediment transport. To this purpose various numerical tools are becoming available which allow for an accurate quantitative assessment of the local flow-sediment-pipe interaction. Among them we find all the models which permit prediction of the dynamics of two-phase flows, like the Level Set and the SPH methods. We here focus on evaluation of the performances of a hydro-morpho-dynamic model, based on the former approach, for use in pipe-soil interaction calculations. Limits and potentials of this rather innovative approach are being investigated using as test cases both well controlled experimental benchmarks and also realistic flow conditions.