meshless streamline tracing does not trace properly

[pausz]

Describe the bug
Streamlines tracing using CNEM produce nonparallel streamlines for a perfect travelling wave

To Reproduce
Steps to reproduce the behavior:

1. Run travelling_reflected_wave('u-a-hs-mb') and then travelling_reflected_wave('u-a-hs-ml')

2. Streamlines should be parallel and look like a collection of vertical lines on the x-y plane. This is achieved with mesh-based methods but not for meshless streamlines tracing.

Expected behavior
both methods should produce the same results

Screenshots

Desktop (please complete the following information):

• OS: Ubuntu
• Matlab version [e.g. 2018b]
• Device specs

(RAM, processor)

Additional context
Add any other context about the problem here.