When making a wineglass "sing", if the glass is partly full of liquid,
then tiny standing waves appear on the surface. I've always wondered, do
they have a name?
I managed to produce a much larger example of these waves in a swimming
pool. By oscillating a long foam cylinder perpendicular to its axis in
the water, after a few moments a set of "standing waves" appear which are
adjacent to the cylinder and with the antinode peaks oriented
perpendicular to it, like so: