Radial Advection Data Generation

[mtrautner]

Running the data generation .sh script for the radial advection example throws an error in the interp_to_numpy_9.py file because the directory 'examples' needs to be included in the path for the meshfile.

[chldkdtn]

@mtrautner Thank you so much for finding this out. You are welcome to fix this path issue and submit PR. We can review and merge it to main branch.