Long before I wrote the OP piece, I've heard cosmologists on the tv talking about detecting huge unexplainable "flows" in space, so it's not just me, or the people who wrote the river model study that I linked.
Not that I'm claiming that as any kind of evidence, but they do readily use the concept of some sort of flow when it's convenient.
That's not to say that it would be just like a liquid or gas flow.
Other people have treated the river model as a flow of reference frames into a black hole.
I've seen references all over the net to that study, none disputing that it's a valid way to model what's happening at a black hole.
Here is the whole article, if you're interested :
https://archive.org/stream/arxiv-gr-qc0 ... 0_djvu.txt
What I take from it is that it's not ludicrous to talk about space being attracted to a massive body, and disappearing into it. Obviously, if space WERE streaming into a black hole, that space wouldn't know what was causing it to move. Black hole gravity isn't any different to Earth gravity, outside of the event horizon.
What I would like to establish, but can't, is whether the acceleration of the flow would be inversely proportional to the change in radius of a sphere squared.
If you picture a sphere of water, around a draining pipe in the ocean, then obviously, the water nearest the pipe moves fastest, and as you go outwards, it's slower and slower. So the water would be accelerating inwards.
Does the acceleration follow the inverse square law?
I think it would, as the change in volume of the sphere is related to the cube of the radius, so you're dividing radius cubed by the radius, giving r2.
But I'm shit at maths, so that's a guess.