Liquid in a cyclone

[JuhaHo]

Actually, this was all new scene started from scratch - another cyclone.

[Svetlin.Nikolov]

Ah, my idea is for you to try out a Paints preset on a brand new and verify that it works correctly on your side, without anything else that you have in the cyclone scene.

And then we would be able to close in on what node, option or plugin causes the issues you are having.

This would need a lot of back and forth between you and me so we would be able to exclude the factors that don't affect the issue, but unfortunately without the actual scene, we don't have much options.

Thanks!

[JuhaHo]

I rebooted the workstation and it's again simulating. It seems, that the memory has to be cleared every now and then during the simulation. In this time the memory error started when I did a quick job with Photoshop while simulating at the background. Closing Photoshop didn't help alone, the workstation had to be rebooted.

[JuhaHo]

I managed to simulate another 100 frames overnight. This cyclone has a bit different design - now with bottom valves. The idea is to fill the cyclone to the bottom valves. However the flow turns upwards before it hits these valves. That's the point where it should get the counter pressure making it climb upwards. Now the cyclone itself is causing the counterpressure. Is there any idea on how to solve this? The fluid is supposed to be non newtonian.

[JuhaHo]

I'm still stuck with this project. I just got my simulation rejected by the client. It seems I need to start this project all over again. The problem is that my Phoenix simulations are not acting by laws of physics at all. It seems to be quite simple, but somehow Phoenix manages to make a mess of it. When the liquid in real life goes down in my simulation it's going up and vice versa.

Any ideas what I should try. The client is beginning to be impatient with me.

[Svetlin.Nikolov]

Let's break the task down into smaller parts and fix them one by one.

How does the issue with the liquid moving up look like in motion, could you send a video?

Cheers!

[JuhaHo]

Thanks Svetlin,

Once the system is filled it's hard to see how the liquid behaves internally. When the heavy tyFlow particles are simulated with fluid force operator, it can bee seen that particles are going up instead of going down. When the outgoing velocity is too low, liquid just falls. When it's sufficiently high to have the liquid going down on cyclone walls there seems to be a counter pressure at the bottom of the cyclone which blocks the liquid and particles from falling down as intended.

[Svetlin.Nikolov]

Try enabling the Velocity preview or the Velocity Streamline preview so you can better see what the liquid's speed and direction is and understand which is the thing that makes it move unnaturally:

[JuhaHo]

Thanks,

I'm not sure how to interpret this, but here are the streamlines. Anyway the flow should go down near the walls and the rotate in the middle. It seems there's no straight up lines. There's also a gap, where flow goes down through this narrow area.

[JuhaHo]

I was wondering,

We know the how many liters/second goes into cyclone. Is it possible to calculate correct value for Outgoing velocity parameter accordingly?

[Svetlin.Nikolov]

Hey, how can I help with the preview interpretation? If you are wondering about the direction, switch from the streamline preview to the regular velocity preview. The Preview rollout should be a tool that can help you understand any situation if you look closely.

Cheers!

[JuhaHo]

You mean like this:

[Svetlin.Nikolov]

Please disable auto range and adjust the min and max of the shown velocity manually so it shows more meaningful data: https://docs.chaos.com/display/PHX4MAX/Liquid+Preview

[JuhaHo]

Thanks,

Here's new. What is missing then? There should be a vertical flow in the middle going up as well as under the narrow gap going down.

[JuhaHo]

I asked Chat-GPT for instruction on how to correctly calculate correct Outgoing Velocity value. Apparently it's not possible to calculate correct value even when we know the fluid speed and cut section area.