step 1, create your shape:
For this tutorial I'll use a circle. I'll give it a pseudo 3d look by using a radial gradient and moving the center of gradient to the top left.
Duplicate (ctrl D) or clone (alt D) this shape.
Flip vertically (V)
Move the mirrored shape to the bottom (for now, I'll call it "mirror")

step2, Apply a turbulence filter :
select the mirror.
launch the filter editor (menu filter/filter editor).
The dialog is made of 3 panels.
the (top) left contains a list of the fillter. it shuld be empty if you start with a new document.
the right part will show what the selected filter is made of (empty too).
the bottom will show the options for the (currently selected) effect of the filter.
click new to create a new (empty) filter => a new entry is created in the left panel
give it a name.
search in the dropdown list (at the right of "add an effect") for turbulence.
click "add an effect". you should see a new entry in the right panel.
(in the left panel) check your filter. the mirror should be replaced by some pattern.
In the panel at the bottom one should see the options of the turbulence filter.
Experiment with them
. there are two types of turbulence with different 'feelings'.
. set the octaves to higher values to get more detailled patterns (it uses more cpu so if you don't need it keep it low).
. increase base frequency so that the pattern repeat itself more frequently.
. ignore "seed" slider (it's of no use 90% of time)
to make the turbulence looks like a ripple YOU NEED TO SET DIFFERENT BASE FREQUENCIES FOR HORIZONTAL AND VERTICAL (click the "link" button so that you can set both of them)
Use the following settings
type:turbulence
freq: 0.01 and 0.05
octave:1
seed: whatever you want.

step 3, use this pattern to distort your shape.
in the dropdown liste, look for displacement map. click 'add an effect'.
in the right pane you should see a displacement map item below the turbulence we just added.
this item has two entries (triangles).
the first one is used to tell what we want to distort.
the second one indicates what we want to use as a source of distortion.
link the first entry to "source image" = click the first triangle and drag the cursor until you reach the text that is rotated on the right.
link the second entry to the first stage of ouf filter = the turbulence effect.
Now go to the options of the displacement map and change length.
Enjoy.
see step 3
This is the end of part 1.
Your image should look like this

in the next part we'll see how to change the size of the ripples along Y axis.