Waves on a slope

Earlier this year at Forscherfreizeit Ratzeburg – the summer camp at which Conny, Siska, Martin, a bunch of teenagers and myself spent a week sailing, exploring and playing with water – I spent a good amount of time staring at waves hitting the wooden boards that form the slip in the port. They create a nice slope with a very interesting structure, especially at the joints where the angle of the slope isn’t exactly the same.

Watch what happens when the wave approaches the shore (and focus on the left part of the picture, where it is clearer):

At first, it arrives pretty much as an ordinary wave.

Screen shot 2015-09-26 at 4.40.53 PM

As it is running up the slip, you start seeing the structure of the boards below.

Screen shot 2015-09-26 at 4.41.14 PM

As the wave becomes steeper and steeper, the front one is being slowed down more than the second one, because it is in shallower water (and we all know that the phase velocity of shallow water waves depends on the water depth, right?).Screen shot 2015-09-26 at 4.41.34 PM

Eventually, they form one steep wave and break.
Screen shot 2015-09-26 at 4.41.54 PM

Watch the movie to see it happen:

For more waves on a slope, check out these posts (Norway, Hawaii).

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