Once again, ITI will be attending this year’s AIAA Aviation Forum from 25th to the 29th of June and will be presenting papers on our research into two cutting-edge applications in aerospace. The forum attracts the best aerospace companies and industry professionals from around the world for a week of conference talks, workshops and exhibitions to help develop future technologies across all aspects of aviation.
ITI will be presenting “Enabling virtual topology for high quality CFD surface meshing of complex CAD geometry” and a second joint paper with Cambridge Flow Solutions (CFS) on “Morphing a CAD model to match a level set optimised shape”. Both papers focus on ways to automatically clean-up and prepare geometry for downstream simulation processes.
Virtual Topology for CAD clean-up
CAD clean-up has been highlighted as a regularly performed process prior to calculating any mesh on a model. It is a bottleneck in the process and is often a costly manual task which slows down the simulation life cycle. Automating these manual clean-up tasks provides engineers with a much faster, repeatable and reliable way of improving the available geometry.
Excessive fragmentation of surfaces in a CAD model is commonplace in modern CAD systems. This can make meshing a difficult task which generates element size changes between a neighbouring large surface and a fragmented surface. One way of addressing this issue is to connect faces together to form larger “zones” creating a virtual topology layer which provides meshing algorithms with a simplified view of the CAD surfaces to ease the job of meshing. Virtual topology provides us with a non-destructive, easily reversible and adaptable way of modifying CAD models to suit mesh generation needs.
1388 CAD faces “zoned” into a single virtual topology surface
Along with outlining the methods used to generate this new virtual topology, we will show some examples where extensive areas of CAD geometry have been meshed successfully using virtual topology.
Linear mesh across feature lines in the CAD model
“Enabling virtual topology for high quality CFD surface meshing of complex CAD geometry” will be presented on the 27th of June as part of session FD-45 at 14:30 EDT.
Morphing CAD Geometry
When exploring a new design space, engineers require flexibility and efficiency, so they can incorporate new results found during the simulation process into their CAD models. This is often a highly iterative process requiring technical manual edits to the original CAD models on each pass through the simulation loop which can be time consuming.
However, by using the simulation results to provide deformation information, we can morph the original CAD into a new design to then pass back into the simulation system for further analysis. This automated iterative process gives engineers a new way to explore a design space without the need for manual intervention. Coupling this morphing process with genetic algorithms to guide the search provides a wholly automated process to design and discover novel CAD geometries.
Using the mesh morphing technologies which will be available in the upcoming CADfix 12, ITI partnered with CFS to apply this new morphing technology to the output from the CFS Level-Set based morphing technology available in BoXeR to produce new designs for various geometries.
On the left; original CAD, on the right; morphed CAD after design space exploration.
The paper outlines the process in detail and shows some examples of this new morphing process being applied to a cooling hole geometry.
The work completed in this paper has received financial support from Innovate UK via the GHandI, GEMinIDS and AuGMENT projects.
“Morphing a CAD model to match a level set optimised shape” will be presented on the 25th of June as part of session MDO-01 at 10:00 EDT.
For more information on any of the technologies we will be presenting at AIAA Aviation 2018, 