New Recruit Extends QED Naval’s Wind, Wave and Tidal Loading Capabilities

QED Naval are pleased to welcome Thomas Nevalainen to the team. Thomas joins QED Naval from Strathclyde University where he is about to complete his Ph.D. His thesis entitled “The effect of unsteady sea conditions on tidal stream turbine loads and durability” allows QED Naval to extend its wave and tidal loading capabilities and add BEMT methods to calculating turbine loads as part of a more streamlined optimisation process for QED’s Subhub foundation structure. CFD methods can then be used to assess the finalised design.

Thomas will take over the management of access to the Hartree supercomputer which is used to improve turnaround times on large models and increase the speed of learning from weeks to days. QED Naval have access to ANSYS Fluent and X-Flow on the Hartree supercomputer. Fluent is a sophisticated CFD package that provides access to a large number of turbulence models and mesh developments such as polyhedral meshes that streamline the size of the model and improve accuracy. However, despite its sophistication it tends to be sensitive cell quality so a great deal of time is spent generating good conformant meshes both in pre and post processing results.

Highly structure ANSYS Fluent numerical model domain setup to yield accurate results.
Highly structure ANSYS Fluent numerical model domain setup to yield accurate results.

 

Numerical model inner domain cell conversion from tetrehedral to polyhedral to yield a more efficient solution and accurate results.
Numerical model inner domain cell conversion from tetrehedral to polyhedral to yield a more efficient solution and accurate results.

Thomas also takes over responsibilities for utilising the other enhanced capability using X-Flow provided by FlowHD. It allows QED Naval to reduce the pre/post processing time using Lattice Boltzman cells domain that is self-adaptive and easily controlled by the user in terms of vorticity in the model in the areas of interest. It combines this with fully transient, LES turbulent model which resolves the largest turbulence fluctuations in the flow while the smallest eddies are approximated for increased efficiency. The self-adaptive cell capability makes it much easier to conduct rigid body motions such as assessing tidal turbine performance characteristics. From the work conducted to date the tools were well validated using the Subhub performance model tank testing results and assessment of Tocardo’s T1 tidal turbine against their specified performance data.

Velocity contour plot of Subhub combined with a Tocardo T1 tidal turbine to demonstrate the performance capabilities of Subhub.
Velocity contour plot of Subhub combined with a Tocardo T1 tidal turbine to demonstrate the performance capabilities of Subhub.
Velocity contour plot for the Tocardo T1 tidal turbine. This stand alone model was used to validate the software against performance trials conducted at Den Oever.
Velocity contour plot for the Tocardo T1 tidal turbine. This stand alone model was used to validate the software against performance trials conducted at Den Oever.

QED Naval offer these capabilities to other marine renewable companies at competitive rates. The main advantage of this work is it can be used to determine what the design loads are on full scale structures without having to go to the expense of building a prototype. Hence, these assessments can minimise the technical and commercial risks of developing marine renewable structures and turbines.