A3 - Hydrodynamics of offshore megastructures and impact processes in and with the marine environment

The hydrodynamic stresses acting on offshore megastructures as well as the deducible expected load history are defined as the superordinate goals of subproject A03. A further goal is set on the modelling of structure-induced flow processes as well as effects in and with the marine environment in close collaboration with the subproject A04.

A good understanding of hydro- and oceanographic impacts on conventional marine infrastructures has been developed. The working hypothesis of subproject A03 assumes, that the dimensions, the degree of construction, the exposition and the change in climatic and submarine environment of offshore megastructures induces stronger strains and effects in and with the marine environment over the life cycle of the structure. This hypothesis is based on impacts and interconections known from theory and design praxis for slender and transparent structures. The applicability of such guidelines for offshore megastructures i seither unknown or not proven. Further, the simultaneous appearance of individual components from direction-dependent wind- and swell-waves in combination with directional currents as well as the resulting nonlinear interactions are only understood to a limited degree.

The superordinate goals in subproject A03 in interconnection with A04 and A05 focus on a better understanding of wave-current-tructure-soil-interaction for the design and operation of offshore megastructures.

Methodologically, comprehensive research facilities are available to conduct the acquisition, modelling and assessment of short-term impacts from waves and currents in large-scale model tests, like for example the wave-current-basin (WSBM, Ludwig-Franzius-Institut) or the extended large wave flume (GWK+, Forschungszentrum Küste). For individual load combinations, existing CFD models (OpenFOAM) will be extended to a complex component model for offshore megastructures regarding the superposition of wind- and swell-waves with currents and will subsequently be validated under the use of data from the laboratories.

The following questions will be addressed within and beyond the first founding period:

1. 1.      Which direction-dependend, amplifying impacts from wind- and swell-waves in superposition with currents dominate the hydrodynamic impacts on offshore megastructures?
2. 2.      How can these complex short-term, superimposed hydrodynamic impacts be captured in acceleration factors and a reduced component model?
3. 3.      How large are the effects of load changes due to future varying metocean and morphological conditions over the life cycle of an offshore megastructure?

These goals will be analysed systematically in subproject A03 in interconnection with further goals of A04 by collective design and operation of models both numerically and in the laboratory. Subproject A03 further has a strong interconnection to subproject A05 through the cluster „impacts from wind and waves“ and provides substantial recognitions, information and data fort he digital twin.