Ripple

[BubikolRamios]

This is random side effect, using BGRABitmap twirl filter on top of one of my images.
See circular spots.
How would one go about doing that on purpose, pointing where should it occur by mouse click (center point, diameter,...) ?
Was looking at lazpaint, union of selections can obviously be done, but looks to me complicated even at run time, as I'm (not into depth) used to PS ...

As I see it, one would need 2 circles, one centered inside another, space between them - do something. For each ripple.

EDIT - something close can be done with PS-filter-distort-zigzag. But only close, not it.

[lainz]

It's basically a radial gradient with moire.

https://www.vecteezy.com/video/25416004-pink-moire-circular-gradient-animation-background-2d-rendering-abstract-background

[circular]

While it is rather simple to remove Moiré patterns (by upscaling, applying transform and then downscaling), it is quite complicated to do it on purpose.

However you could simulate such pattern by blending a radial gradient (with sine repetition) on top of the image. Here as the pattern is dark, using the boDarken blend mode could do.

I suggest maybe to experiment a bit with LazPaint. You don't need to use any "selection". Here is a sample image attached as LZP.

The Moiré pattern is made using a radial gradient (with sine repetition) masked with a radial gradient (white in the center, black outside the disk). It is then applied on the horizontal lines using Darken blend mode. Actually, the Overlay blend mode seems to give a more realistic result.

[circular]

Here is an example with Overlay blend mode:

[BubikolRamios]

Note. Click drag inside black box.
https://codepen.io/ds604/pen/VxroVN
also
http://thecodingbus.info/wp-content/uploads/2022/03/index.html