Ripple Effect in 2D

Good morning everybody.

I found an interesting looking function in an openGL book that looks like a ripple in water just after a drop hit it. Does anybody know of a function that I can run on the line so that it looks like a ripple effect? I’m thinking about this:

y = y * sin( PI * t)

where y is the height, and t is the time from the origin.

FYI here is the function:

sinc(x) = sin( PI * x) / (PI * x)

its usually just a hack,
search for “the fun bouncy” page + ripple effect (hopefully u wont hit a lot of porn)