There’s always a debate on choosing the right meshing technique for FEA and CFD simulations. Since meshing is an important part in any simulation process, it is imperative to ensure that a proper meshing technique is adopted. This is essentially a concern for most analysts as the simulation results hugely rely on mesh quality.
It is quite easy to differentiate a bad quality mesh applied on a model against a good one. However, it is very much complex to know whether the mesh model will solve the simulation purpose or not. Despite several mesh-less FEA and CFD codes, meshing is still an important parameter, utilized in most commercial solvers available today.
Automatic Vs Manual Meshing
The process of subdividing the geometry in small number of elements is also a time consuming task, and as such, present available technologies provide users with automatic meshing feature to ease up the simulation process a bit. It is however also true that a mesh generated automatically might consist of errors and cause the results to deviate.
Manual meshing on the other hand is quite time-consuming but far more accurate. However, applying meshing to the geometry requires a good experience and knowledge about the system being simulated. While automatic meshing simply makes an educated guesses to resolve the geometry and produce a mesh model, it is the analyst who has to decide whether the model is acceptable or not, based on his experience.
A novice on the contrary has to rely on the software’s automatic meshing capability. In order to target non-experts, simulation software providers provide automatic meshing feature to bypass the long manual meshing menus. However, the automatic meshing capability might not be suitable for specific problems.
For anisotropic geometries such as flow inside a long skinny pipe, it is not ideal to use tetrahedral elements often used by automatic meshing feature; since it uses far more number of elements that required. Similar case is also for a leading edge of an aircraft wing projecting against high velocity field, requiring special mesh handling around the affected regions.
However, automatic meshing feature is also provided with controls to manually refine the mesh, which can improve the analysis of high stress concentration regions more effectively. This helps non-experts to rely on software features without having any fear of walking off the cliff.
A more reliable approach however is to employ both the techniques simultaneously. Creating two mesh models – one using automatic meshing and the other with manual tools can help in establishing relationship between the two. Comparing the results will help in determining the flaws and improve the mesh model further or eliminate the use of time-consuming manual meshing technique.
Mehul Patel specializes in handling CFD projects for Automobile, Aerospace, Oil and Gas and building HVAC sectors.
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