Note: I am actually also searching for the term in German. That is why I posted this here (as opposed to the language SE's), besides me looking for this term in a mathematical/technical context.
I'd like to say "the points are shifted ______ly as the radius of the circle grows".
With "shifted" I aimed to convey the change of place to be discrete.
Searching I found "radial", "axial" and "circular", of which the first two are probably wrong, while the last one seems to be used predominantly in the sense of "circle-shaped" or "round". However, Merriam-Webster suggests "moving or going around in a circle" as an alternative definition—is this interpretation somewhat usual?
In German, the yield is even less, as can be seen from the Duden entry on "zirkulär".
Best Answer
"Radially" (in my experience) usually refers to a bunch of things spreading out in a circle, like if you drop a water balloon the water spreads out radially.
I'm pretty sure that the word you are looking for is "circularly" or "undergoes circular motion". I am a native english speaker and don't believe I've heard anything else.
Then there's just "circle" as a verb. As in "the points circle back around".
There's also "circumnavigate", although this usually is used in a more metaphorical, literary sense rather than actually moving on a circle.
Given your context, it seems like the best option is "the points rotate about the center as the radius of the circle grows"