Ocean Waves Improvements, esp. Stokes Waves

[mbkuhn]

Summary

Bug fix for stokes waves, adding feature of wave length calculation, generalizing and de-hardcoding ocean waves code

Pull request type

Bugfix + Feature

Please check the type of change your PR introduces:

Checklist

The following should accompany this PR:

• [ x] new unit-test(s)
• [ x] new regression test(s) pass

This PR was tested by running:

• the unit tests
  • [ ] on GPU
  • [x] on CPU
• the regression tests
  • [ ] on GPU
  • [ ] on CPU

Additional background

With small water depths, the stokes waves velocities seemed reasonable before the bug fix, but with a depth of 10 m, the velocities in x were on the order of 1e20, due to the mix-up of variables m and n.

Issue Number: N/A

[mbkuhn]

@gdeskos would you be able to take a glance at this PR, mainly the function that calculates wavelength?