Heat Transfer using custom image

[dokken]

First of all, please use 3x` encapsulation to make your code copyable, Ref

Can't create the form of the navies stokes equations,

Please provide a minimal reproducible example with 3x` formatting, i.e. ```python #add code that reproduces your error here ```

Please also make sure that the complete code is added (including definitions of your image).

And finally if you scale your mesh with l, then this has to be taken into account when computing i and j