Mesh convergence
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The mesh convergence study is a numerical analysis that aims to determine the optimal mesh size for a given problem. The goal is to find the smallest mesh that provides accurate results. This is important because using a mesh that is too coarse can lead to inaccurate results, while using a mesh that is too fine can be computationally expensive.

The mesh convergence study involves running the simulation with different mesh sizes and comparing the results. The results are typically compared in terms of the error in the solution, which can be quantified using a metric such as the L2 norm of the difference between the solutions obtained with different mesh sizes.

In general, the error in the solution decreases as the mesh size decreases. However, there is a point at which further decreasing the mesh size does not significantly reduce the error. This point is known as the convergence point, and it represents the optimal mesh size for the problem.

To perform a mesh convergence study, you can follow these steps:

1. Edit the ``.geo`` file to change the mesh size. Start from a coarse mesh and gradually refine it by decreasing the mesh size ``cl1``.
2. Follow the entire workflow to generate the mesh, run the simulation, and post-process the results for each mesh size.
3. Compare the results obtained with different mesh sizes (side by side) to determine the convergence point.