Seabed wind farm interaction
This leads to (1) the seabed changes form (erosion even without wind turbines, under storms, travelling bed forms, etc.), and (2) local erosion takes place around the individual foundations. The key factors in the design of offshore wind turbine foundations namely (1) maximum loading to determine the size and depth of the foundation; (2) fatigue load to determine the wall thickness and the shaping of the structural components; and (3) eigen frequencies to determine the operation of the turbine are all heavily influenced by (1) the erosion and scour processes and (2) the processes related to the foundation and the soil interaction. The purpose of this project is to make better analyses of the erosion and scour development around wind turbine foundations, and better analyses of the soil structure interaction. The work is undertaken under four work packages: WP1. Fundamental knowledge; WP2. Effective methods to predict scour over long period spans; WP3. Interaction between structure, flow and soil conditions; and WP4. Natural seabed changes and interaction with seabed forms. The project will enhance the basic knowledge of (1) the erosion and backfilling process in changing sea states, and (2) the interaction between a rocking foundation and the soil, under different conditions, for instance, when the flow conditions change from current-dominated to wave-dominated (during a storm)
Foundation of wind turbines offshore is complex, and makes up to about one third of the overall investment. A complicating factor is that the seabed consists of loose material (sand, silt), which moves under the influence of waves and currents. Large scale sand waves (from hundreds of meters to several kilometers) may also be present on the seabed, to further complicate matters. When wind farms are erected offshore, heavy erosion (or scour) will take place around each individual turbine foundation. This is a threat for the stability of the turbine structure. Therefore these structures are almost invariably protected against scour with rock protection installed around the foundation, although “no protection” is also a viable option. Furthermore soil processes across the foundation depth is also an important factor. This project has addressed the above problems via laboratory experiments and advanced computational-fluid-dynamic and soil-mechanics methods. The results include: Process understanding, experimental data, validation of the advanced numerical models, data from numerical experiments, and design guidelines and recommendations with regard to seabed-windfarm interaction. The project results have been disseminated (1) in journal papers, conference papers, reports, etc. (see a complete list of publications at http://www.external.mek.dtu.dk/personal/bms/LIST OF PUBLICATIONS_FINAL.pdf), and (2) at an end user conference (see web site http://sbwi.dhigroup.com/end_user_workshop/).
Key figures
Category
Participants
| Partner | Subsidy | Auto financing |
|---|---|---|
| DHI | ||
| Aalborg Universitet (Fredrik Bajers Vej) | ||
| LIC Engineering A/S |
Contact
Nils Koppels Alle, Bygning 403
DK-2800 Kgs. Lyngby
www.mek.dtu.dk
Sumer, B. Mutlu , 45251423, bms@mek.dtu.dk
Øvr. Partnere: DHI - Institut for Vand og Miljø; Aalborg Universitet. Institut for Byggeri og Anlæg; LICengineering
