
The water has momentum or extra pressure at the top; ie the water would loop-the-loop and exit.
I suspect you might need to 'push' the water at the top tho.
( , Sun 6 Jan 2013, 14:33, Reply)

So some kind of flush? Would it really loop-the-loop, though? Wouldn't it just form a well at the nadir, and fill it all the same? I mean, I'll bow to your knowledge - I make no claim to expertise - but I can't get my head around how it'd work.
( , Sun 6 Jan 2013, 14:36, Reply)