I gave what I think to be a short answer as to why that water goes round and around Antarctica. But here is me framing the question that needs to be answered:
I think a cheap and nasty study should be engaged upon to see if the gigantic power of the Antarctic Circumpolar current can be explained easily by wind friction alone. I would doubt it myself. I would think that what we ought to have instead, if relying on wind friction, ought to be a fairly shallow weak sort of affair. Moving around and around but only feebly so. Its a bit like those super-rotating cloud banks on Venus that lack a good conventional explanation. Not much coriolis forces to work with on Venus. Convection remains an upward, randomised swirling force and cannot be press-ganged into explaining persistent powerful horizontal movement. People try to make that convection work in their minds eye for these sorts of things. But they cannot do it, so they move on and delegate these things to the building 7 part of their brain.
Of course even if the wind friction could explain the entirety of this power, we’d still have to have satisfying reasons for the consistency and power of the winds at sea level. But for those who are able to put together some draft back-of-the-envelope calculations to these things, from home and using only satellite data, I think its a worthy undertaking, even if you could never hope to complete the task, without funding and a team from crossover specialties. We don’t want to leave these things as eternal mysteries of life and elephants in the room. What could make the water just seem to act strange and go around and around like that? Think of the machinery that it would take to replicate such a thing artificially? The length and power of the flow of the Circumpolar Current, makes the Amazon rivers efforts, look feeble indeed. This is even the case although the Amazon has gravity working in its favour . No gravity to help out the Circumpolar Current. Plus cold salty water is far more viscous than warm fresh water. The mystery compounds on itself.
The Gulf stream is called a thermohaline current. The Gulf Stream has heat and saltiness differentials working for it. So people assume they have that powerful North-South energy explained and they think there is nothing more to see here. Well you know. I have my doubts about that also. But those explanations, or partial explanations, aren’t there for the Circumpolar Current. So I think its a serious mystery under the paradigms that hold sway at the moment. And I think it ought to be dwelt upon and looked at with much curiosity.