The Airflow Toy
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So I was trying to make a skydiving simulator for stickmen today, involving creating
- Enough airflow to exactly cancel out gravity
- Laminar airflow to let you move around by spitting dust.
In order to do that, I placed some PUMP at the top and bottom of the save. I should've used FAN, but anyway I discovered that a very odd pattern is formed:1669624View Save 1669624
Now I know that the airflow code is some of the oldest stuff in TPT, and from some dev's comments seems to be based off some kind of long-lost Eldritch knowledge, but I was wondering if there's any explanation for
a) why the air column tapers inwards
b) why strange triangles of hypersonic air appear on the edges
c) why the pattern isn't symmetrical
It's strange enough to almost be bug-worthy.Edited 2 times by minecraft-physics. Last: 11th Nov 2014 -
Try using more walls around the edges (at least 3 wall tiles on each side).
Pressure and velocity are reduced in a range of up to 3 wall tiles from the edge, by multiplying by 0.8 for pressure and 0.9 for velocity.
If the pressure in the save is negative, this reduction is effectively a positive pressure source with strength proportional to the magnitude of the negative pressure. So there is air flowing in from the sides of the save, towards the top of the save - this produces the triangles of air around the edges, and the tapering column. The velocity is highest in the top corners because the pressure difference is over a very small distance, as opposed to over the entire height of the save, so the velocity produced is higher.
It's not symmetrical because the pressure reduction is not symmetrical, it's 3 tiles on the top and left, and 2 tiles on the right and bottom. (Velocity is 2 tiles on all sides.) If you remove the wall tiles on the sides, it looks fairly symmetrical (this is probably why the pressure reduction is not symmetrical - so that the resulting effect is symmetrical when there's nothing around the edges).
Edited 2 times by jacksonmj. Last: 11th Nov 2014
