Liquid traveling through a tube

[cb LLC]

Hi We have a logo where liquid travels through a tube. It starts out fast but then slows down. Why does it slow down. When water travels through a water hose it has a bout the same speed through out the hose. Anyway to have same speed of liquid traveling though tubes Thank you

[Svetlin.Nikolov]

Hey,

This is because Phoenix or the other mainstream VFX simulators do not simulate pressure. Try guiding the liquid using a path follow force.

Cheers!

[gregvfx]

WOW, super piece of information!

[Ivaylo Katev]

just to be more correct - the simulators have pressure calculation, it is perhaps the most important part, but the pressure effect decreases rapidly with the distance, and is very calculation expensive to extend it (the conservation parameter does exactly this).
the path force is better solution , in fact it is the only solution, you can not achieve realistic pressure effect for long pipes in any reasonable simulation time.

[Svetlin.Nikolov]

Technically the source injection and conservation try to mimic actual pressure simulation, but they are not complete solutions, and we don't claim to support that. Some processes in both the grid and FLIP simulators can produce results that might look like pressure effects, but the actual process is more complex than that and gets even more interesting as velocities increase. As Ivaylo said, there are computational limits on it as well.

[cb LLC]

Thank you, guys. I did not know it had no pressure

[Svetlin.Nikolov]

It's going to act like it has some pressure, but not enough to drive the fluid through a long tube though