The capability to understand and investigate the motion of liquids and gasses in detail is of high importance in a wide range of engineering disciplines. Earlier, this type of assessment was nearly always based on physical model tests, but technological development has pushed the use of Computational Fluid Dynamics (CFD) and today, it is a widely used tool in the engineering design and analysis process.
DHI has applied CFD for the last 15 years and developed an in-house CFD system named NS3. The system has been applied and developed in a large number of research and consultancy projects, please refer to the NS3 Capabilities for further information. A recent application of NS3 has been the simulation of wave run-up and slamming force on a gravity type wind turbine foundation.
A larger number of offshore wind-farms are presently under construction and observations from one of these farms have clearly shown that wave run-up can be quite significant. There has generally been a tendency to underestimate the wave run-up in the design of offshore structures and the complicated run-up process has been investigated in a NS3 application. The NS3 applications did cover simulation of an experimental set-up as well as a real wind mill site.
The experimental set-up did cover different water depths, wave heights and bottom slopes. The comparison between simulation and experimental data did show a good agreement.
Application of the NS3 model to an already constructed wind mill site did demonstrate that NS3 simulates run-up and slamming forces that would result in the same damage to the mill foundation as has been observed at the site.
NS3 wave run-up