Engineers at COWI, the Danish-headquartered international consulting group within engineering, economics and environmental science, use DNV’s market-leading software solutions Bladed, Sesam and Sima for integrated computation of wind turbine and foundation loads in the design and structural analysis of fixed and floating wind turbine support structures. The use of Bladed and Sesam together enable more accurate initial designs, with better load representation and more optimised foundation design. Optimizing the design early allows COWI to reduce risk of costly changes.
COWI engineers at forefront in fixed and floating offshore wind turbine support structure design
Jason McNeill, senior engineer and project manager at COWI, works on offshore wind projects across the globe, focused on directing and managing high risk projects that support the design, manufacturing and construction of wind farms. He has been working on integrating the two workstreams from Bladed and Sesam for fixed offshore wind turbines, allowing calculations in the two programs to run continuously, which means that a greater number of iterations in the design can be analysed over a shorter period of time.
COWI’s marine structural engineer Stian Fiskvik is a user of Bladed, Sesam and Sima workflows for the design and analysis for fixed and floating offshore wind turbine load and sub-structure analyses. He is based in Oslo, having attained his M.Sc. in Marine technology from NTNU in Norway in 2020.
Initial design is more accurate with Bladed and Sesam
McNeill explains how the integration of Bladed and Sesam helps the engineers. “One of the reasons we like this workflow is because we can bring our initial foundation design closer to our final and more refined design, earlier on, meaning there's less risk,” he says. One of the key areas of improvement is that the amount of steel being used for the foundation can be determined more accurately at an earlier stage, which brings valuable predictability to the projects.
Wind turbine manufacturers (WTMs) usually send over preliminary loads, which can work for monopile structures, but often do not adequately represent the final product for complicated structures such as jackets. The use of the integrated workflows improves the accuracy of fatigue loads on the jacket structure during initial design internally in COWI. “Our immediate goal right now is to produce better initial designs, so concepts that are closer to the final design. That allows us to have happier customers who are not seeing large changes,” says McNeill.
There are additional examples of the benefits of more accurate early design, for example for customers exploring areas of development in areas exposed to seismic risk. “Now that offshore wind is moving into different areas of the globe, we have customers who are facing seismic design questions and they don't know how to answer them at an early stage of the project,” says McNeill. “We have been making use of the seismic functionality in Bladed to do quite detailed seismic analysis at a very preliminary stage of projects.”
COWI is also working on developing libraries of turbine models and their integrated load analysis data, bringing together turbine development and foundation design development. The library of turbine models makes COWI more agile, ready to go on projects, as only slight modifications or changes to the models may be necessary on each specific project.
Floating offshore wind – coupled analyses and simulations
The design of floating wind turbines is more complex and dependent on computational power, as the analyses must take floater hydrodynamics and mooring loads into account. DNV offer coupled analysis and simulation using Bladed, Sesam and Sima to accurately capture the complex dynamic response of floating wind turbines.
Fiskvik notes that the coupled effects are more accurately captured using DNV’s software. “By bringing the foundation and the turbine together in the simulations, the analysis can help us capture more coupled effects between the turbine and the foundation. With a better load representation, that gives us a better basis for the foundation design,” he says.
DNV offers workflows for floating offshore wind turbine design with Bladed, Sesam and Sima as shown in the image below.
Unparalleled domain expertise
Bringing Bladed, Sesam and Sima into the integrated workflow is supported by DNV software and domain experts. There is close communication between DNV and COWI, and the engineers at COWI see their feedback continuously included in new releases of the products.
DNV’s expertise in offshore wind is undisputed. “The general experience at DNV and the software support is very, very helpful,” says McNeill. “I think we would be hard pressed to find the same level of support somewhere else. I think it's a very good cooperation.”
COWI, founded in Denmark in 1930, is a leading international consulting group within engineering, economics and environmental science. COWI creates value for customers, people and society through a unique 360° approach. Based on world-class competencies of 6600 employees in offices across the globe, COWI tackles challenges from many vantage points to create coherent solutions.
- Customer name: COWI
- Web address: cowi.com
- Market: engineering, economics, environmental science
- Product: Sesam and Bladed
Why we chose DNV:
- Heavy analyses with a large number of load cases can be solved fast by the use of cloud computation
- DNV are one of the front runners when it comes to keeping up with developments in the offshore wind market
- Sesam is "tailor-made" to solve offshore wind foundation analyses
- The user friendliness of Sesam, especially the GeniE tool, means that engineers can start using it quickly with a low threshold for learning
- The software has a large pool of users, easing recruitment of engineers
This is what we gained:
- Close cooperation with DNV has led to developments of products and software, benefiting COWI
- Quick response to requests for new developments
- One go-to tool for structural analysis, both for bottom-fixed foundations and for floating foundations
- COWI, in a leading position in the market for offshore wind foundation design, is able to keep up with the latest market demands
- Very good support from DNV