Swift, local, surface, bottom and slope currents have been observed at several locations on the Norwegian continental shelf and slope. The high topographical resolution of laboratory models reveals how narrow and filamentous many of the flow features can be, posing a challenge for monitoring currents along the pipelines from deepwater fields to coastal terminals. The laboratory model results have demonstrated that numerical models need high resolution on slopes and in narrow passages to accurately simulate the flow fields for risk assessments. This is most efficiently done with finite element models. The paper shows, by the use of a few selected examples, how the combined use of laboratory and numerical models, together with field measurements at key locations, constitutes a cost-effective method to establish a data base of relevant quality and sufficient resolution for rational Pipeline design.
The ocean current environment is one of the most uncertain factors in assessing loading and safety design of pipelines and offshore structures. Laboratory model simulations have often paved the way for choosing and developing the proper strategy for field measurements and numerical modeling. The synergy of combining laboratory models, numerical models and field measurements, using the inherent advantages of all, has proven to give reliable results, and provides the basis for qualified data cost-effectively. The independent approaches give confidence in the results of each, thereby minimizing the need for extensive field measurements. The objective of the paper is to show this by examples taken from recent engineering studies. Laboratory simulations, validated to selected field measurements, have provided benchmarks for numerical models. The numerical models provide further details, and extrapolate the parameters to values that are hard or impossible to achieve in the laboratory. The paper focuses on the wide range of environmental conditions that are encountered along pipeline routes from deepwater fields to coastal terminals,
