Stipendiatstilling 10 SINTEF (2021-2023)

When testing new designs of floating structures, an unavoidable step is model testing in hydrodynamic laboratories. The experimental reproduction of open ocean waves in a small working area around the model to be tested is a topic generally well understood. Many projects have recently aimed at building floating structures of larger scale, such as floating bridges, solar islands, or arrays of more conventional structures. This recent trends brings about two new challenges. On one hand, when testing large scale floating structures in an Ocean basin, the working area is not small anymore, but covers most of the basin. On the other hand, when ocean waves approach coastal regions, they are modified by for instance decreasing water depth, islands, skerries, coastline and fjords. In particular, waves can vary spatially: they are inhomogeneous. Research is needed for high quality experimental modelling of large scale floating structures in coastal waves. The objective of the PhD study is to establish methods for experimental and numerical modelling of coastal waves in hydrodynamic laboratories. [11:42] Sebastien Lafleche Engelsk versjon (si fram om det er for langt eller noe annet): When testing new designs of floating structures, an unavoidable step is model testing in hydrodynamic laboratories. The experimental reproduction of open ocean waves in a small working area around the model to be tested is a topic generally well understood. Many projects have recently aimed at building floating structures of larger scale, such as floating bridges, solar islands, or arrays of more conventional structures. This recent trends brings about two new challenges. On one hand, when testing large scale floating structures in an Ocean basin, the working area is not small anymore, but covers most of the basin. On the other hand, when ocean waves approach coastal regions, they are modified by for instance decreasing water depth, islands, skerries, coastline and fjords. In particular, waves can vary spatially: they are inhomogeneous. Research is needed for high quality experimental modelling of large scale floating structures in coastal waves. The objective of the PhD study is to establish methods for experimental and numerical modelling of coastal waves in hydrodynamic laboratories. The PhD is divided in two main parts: improving wave quality in a large area of the basin, and investigating inhomogeneous waves in coastal regions. For each one of them, a series of experiments has been carried out in SINTEF Ocean's Ocean Basin at Tyholt, Trondheim. First, the quality of waves in the basin was documented in a large area of the basin. A numerical method was developed to model the wave field, and was validated experimentally. A methodology to improve wave quality by using a multiflap wavemaker was proposed and tested. Then, a methodology to generate experimentally inhomogeneous coastal waves was also proposed and tested experimentally. This methodology applies when the local wave conditions are known. In the case where the local wave climate is only partially known, which additional assumptions are needed was also investigated. The results of the study have been compiled into two journal articles and a conference paper, all accepted for publication.

Det er utviklet ny forståelse og metoder for å generere hav og kystbølger i et eksperimentelt miljø. Målet her har vært å forbedre kvalitet og forståelse av bølger ved bassengforsøk. Det er videre også laget nye numeriske modeller for å håndtere dette. Dette er viktig for å kunne gjennomføre modelltester i havbassenger og sjøgangsbasseng av hav og kystkonstruksjoner.