Viscosity alone can’t account for the water being pulled into the blaster. Think about other properties that can make fluids move.
The combined pressure and viscous forces make up the molecular stress considerations for the fluid motion.
Yes! This difference is created because the water being pulled in is affected by atmospheric pressure while the pressure inside the tube is created by expanding the capacity.
This causes water to flow up the tube to relieve the pressure difference.
Have you heard of momentum before?
Because there is a pressure change in a contained system, there is also a change in velocity that must be considered.
This term to consider is called the bulk flow.
To evaluate it within the volume, we calculate momentum per volume.
It’s basically how much motion an object has and is mathematically defined by mass times velocity.
No, what’s that?
Bulk flow is evaluated both in the direction of the fluid as well as perpendicular to the flow. Yes, that’s density!
Do you know what mass per volume is?
So, if the flow is turbulent, then the flow is moving in multiple directions, right?
Yes, that’s density!
Depending on how fast the pump is pulled on the water blaster there may or may not be bulk flow to be considered.
Yes! And when the flow is laminar then it can be assumed to only be flowing in one direction.
Okay! I think I understand now. Thank you both so much!
