a rest day, some wave contemplation

by Graham

Kelvin-Helmholtz waves in Saturn's surface. Waves are everywhere!


I’m still resting my back, so I don’t have any new windsurfing photos, though I think there was some fun jumping at Hookipa. But before moving on from yesterday, I think it’s funny how the sail in the post’s photo from 1983 is a 4 batten with an outline similar to some seen on the water nowadays. Ha!

There were some interesting wave clouds seen over the weekend. It seems they’re already all over the internet, but I thought I might as well post them.

But first, here is the wiki entry:

Kelvin-Helmholtz instability, after Lord Kelvin and Hermann von Helmholtz, can occur when velocity shear is present within a continuous fluid, or when there is sufficient velocity difference across the interface between two fluids. One example is wind blowing over a water surface, where the wind causes the relative motion between the stratified layers (i.e., water and air). The instability will manifest itself in the form of waves being generated on the water surface. The waves can appear in numerous fluids and have been spotted in clouds, Saturn’s bands, waves in the ocean, and in the sun’s corona. The theory can be used to predict the onset of instability and transition to turbulent flow in fluids of different densities moving at various speeds. Helmholtz studied the dynamics of two fluids of different densities when a small disturbance such as a wave is introduced at the boundary connecting the fluids.

Now, here are the photos:



Another interesting note on shapes:

I met with an old friend, Micah Nelson, and now he lives as an artist in California. Check out his work here. But I mention him with respect to waves because he’s lately been using cymatics (the study of visible sound and vibration) to display the shapes and patterns that music makes when resonating through water. Check the video below and the other videos on his channel (make sure you check out the amazing variety of forms the sounds takes in the water):



Oh, and there is an interview with me on Zakel Windsurfing.