What is the equation for this wave?

Question

So it would be hard to describe it, it's better to see it yourself:

http://physics.info/waves/surface-wave.html (Angular velocity of rotating points is constant I presume)

What is it called? What does it describe in real world and what's the y=f(x-t) type equation for it?

I tried exp(cos(x-t)) but doesn't really match.... It must be something easy

Answer 1

My guess is that this is not linear function. The linear version of it would be cycloid when the angular velocity of the rotation is constant, here is the demo

https://www.desmos.com/calculator/hs8tmubs1g

But crests not being pointy but rather smooth leads me to think that this is a non-linear motion, maybe elliptical or something like this:

https://www.youtube.com/watch?v=PICtFKNlXb8

Answer 2

It's a curtate cycloid.$$$$$$$$