PG2 Interesting Phenomena & Fluid Physics

[Elmach]

Here, I will be recording all the experiments and pictures I've made with the new wind engine.
You too can post here and post interesting phenomena you have found in PG2.

SPOILER: Click to show

I added this section because I often do experiments on a particular type of world. Side-LOOP for all of them. I name each using the positions of the blocks:

• Room: Blocks on all sides
  
• Wind Tunnel: Blocks only on top and bottom
  
• Torus: No blocks at all on the edges
  

And add prefixes, such as

• Semi-Anti-Gravity (SAG): Top row of blocks become BH
  
• Anti-Gravity (AG): Top row of blocks become BH, bottom row becomes WH, G-off
  
• Modified: Small minor modifications are made. Explained in detail.
  

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When left alone, a Torus will quickly have all wind going in the same direction, and will eventually slow down and stop. The second step is very slow.
Wind does not pass through diagonals, unlike in PG1.
No matter how much the wind changes outside any region enclosed by block and having no wind, the enclosed region will never have any wind. Alternatively, two regions separated with block do not interact.
In a Modified Torus with added blocks, the wind will shift such that it minimizes the surface are perpendicular to the wind.

The below quote links to a post I've made with the first few pictures and notes I've made.

Dec 11, 2011 22:16:57 GMT Elmach said:

Since my first posts on PG2 were in the PG board, I'm copying them here.

Again, PG2 is beautiful.

Dec 10, 2011 7:17:03 GMT Elmach said:

This is... beautiful.

Make SIDE-LOOP, remove all block, add powder and wind. It's beautiful.

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Beautiful.

I could watch this for days.

Now if I could only duplicate this.

EDIT:

Beautiful.



I love PG2.

EDITx2:



All of these images were created by removing all block, setting it to LOOP, adding lots of powder, and then adding wind so that it all flies in a direction. I add a small puff of wind in another direction.

EDITx3:

Rolling hills, anyone?

EDITx4:

In the end, if you have no block and SIDE-LOOP and don't touch it at all, there will just be wind going in one direction. After this, the wind will die down, and it will all fall downwards. The first step is somewhat quick, but the second step is slow. Every picture you see was made on the way to the first step.
EDITx5:

Added spoilers because it made this post very large.

EDITx6:
So I added some block. MOAR PICTURES

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Let the hills roll on forever...

(But they don't)

EDITx7
Gravity. So important, yet so weak.

GET DOWN HERE!

I now love doing this:

Remove all block, add powder and wind evenly, then make a small shape in the middle. I want to study fluid dynamics now.

EDIT:



I didn't realize that wind does not pass through diagonal connections.

On a separate note, while playing with strong wind and curved blocking shapes, I saw the powder collecting in squares the size of a size-1 block. I'm assuming that this is an artifact of the way wind is calculated.

EDITx2:

Well that's odd. The wind tends to move such that the cross section of the blockage is minimal.

I thought for a while that you could make antigravity.

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First:

Then:

It looked like it...
But after a short time, it began falling at normal speed... which looks like floating compared to everything else.

EDIT: Added list of discoveries spoiler. Also, the wind shifting I mention in the quoted post is not counterintuitive at all.
EDITx2: Revising entire post currently.

[Vertigo]

I'll go into this more later, but I don't think air pressure exists at all.



Powder does avoid blue air, but that's because blue air is creating massive spirals that push everything out of it.



Like so. Also, while blue air spirals outwards, green air will spiral inwards.



That took a long time to do though. Gravity was off and speed had to be on 8.

[Elmach]

Agreed. Plus, extremely fast air speeds often look like stripes of blue and green, which is complete nonsense in PG1 terms.

[mdog95]

Okay, so I was just messing around and found this amazing thing I could just watch for days.

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I got this amazing effect with BG blur, gravity on, and the map set up as so:



Block on all sides.

The fans blowing against each other make these magnificent moving spirals that are just incredible. The way I have it set up (it may vary with precise placing of the fans), it looks like waves are breaking on the lower left, and then it transforms into many other spirals. And sometimes, there will be a perfectly cut in half rectangle.

This wind stuff is just amazing.

EDIT: IT also makes some neat stuff with gravity off, but I like the look of the breaking waves c:

And when you remove the block, it does completely different, also spectacular things.

[Elmach]

New room: Anti-gravity chamber

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I took this picture after I started playing with it. Top part is BH.

With this many BH's, the center has ~15 dots height where it is attracted upwards, and the edge has ~5 dots height where it is attracted upwards.

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I placed lots of water and powder on the floor, then around every minute, I flipped G. I discovered:

• 
  A line of BH attracts to the center of it, not uniformly
  
• Powder falls slower than water, but sinks in water. Thus, when I turned G-off, about half the water rose to the top, while the rest was trapped under a powder bowl.
  
  

[Artifact123]

Haha only you would make this Thread, wouldn't you? Love it!