neilds37 Loc: Port Angeles, WA

Guyserman, I.ve been trying to get my head around it since I first chimped it in the camera. The faint wakes are easy to explain. There are no internal combustion engines allowed on the lake's surface and the waterfowl population is quite high with birds paddling in all directions. In the puzzle of this photo, that is the only thing easy to explain. I presented one idea farther back in this thread, and I can argue against it as easy as for it - maybe easier. I have other photos of duck wakes taken on the same day, and not one comes close to that visible in this image.

I think we are all waiting for some photographer on UHH who happens to be a hydrodynamicist to join in with a lerned explanation of what we are seeing. For my previous idea to even come close to working these two duck's feet would have to be pushing back at the same time, the equivelent of a human swimmer doing a breast stroke.

DirtFarmer Loc: Escaped from the NYC area, back to MA

The pattern is formed by a difference between the wave velocity and the phase velocity. You can see similar patterns in boat wakes when viewed from above.

neilds37 Loc: Port Angeles, WA

Thanks for the information, DirtFarmer. I have looked at numerous boat wakes on Google Earth and have never seen anything like this. Also, what conditions precipitate the difference in the two velocities?

DirtFarmer Loc: Escaped from the NYC area, back to MA

It's been a long time since I thought about this and I got the terminology wrong. It's not the wave and phase speeds, it's the group and phase velocity.

https://en.wikipedia.org/wiki/Wake gives more information and even has a photo of a duck with a similar wake. Or google 'Kelvin Wake'.

neilds37 Loc: Port Angeles, WA

Thank you very much for the solution to this problem.

artBob Loc: Near Chicago

Thanks to all, for the whole shebang!

ediesaul

How would you viewers say?[/quote]


The pattern is very engaging! If the photo were mine, I'd lighten the two ducks and cut about a third from the bottom so we are not distracted by the black blob. I wouldn't cut too much from the right because there should be some room for the ducks to swim into.

neilds37 Loc: Port Angeles, WA

The pattern is very engaging! If the photo were mine, I'd lighten the two ducks and cut about a third from the bottom so we are not distracted by the black blob. I wouldn't cut too much from the right because there should be some room for the ducks to swim into.[/quote]

Thanks for your thoughts on the treatment of this photo, ediesaul. I'm not giving this one a "one size fits all" PP. The dark blobs are blue sky reflecting off the water from a broken overcast cloud layer. So far I've cropped from right side and bottom to emphasize the wake track, but that's not my "wall hanging" choice.