The u_x component of velocity is saved with the wrong sign in the VTK file. This is a straightforward fix. It will be a good practice problem for creating a new branch, making the change, and submitting a pull request to main.
The root cause of this bug was an incorrect sign in the horizontal derivatives. The reason the results were still correct is because negative signs canceled out. The fix has been merged to main.
The u_x component of velocity is saved with the wrong sign in the VTK file. This is a straightforward fix. It will be a good practice problem for creating a new branch, making the change, and submitting a pull request to main.