Poiseuille Flow (Viscous Flow in a Pipe)
Push a thick or thin liquid through a narrow pipe and watch the flow profile form — the fluid at the wall barely moves, the centre races, and halving the radius cuts the flow to a sixteenth.
What you can adjust
- Fluid
- 1 – 10000 mPa·s
- Pipe radius (R)
- 0.5 – 10 mm
- Pipe length (L)
- 5 – 100 cm
- Pressure difference (ΔP)
- 0.1 – 50 kPa
- Animation duration
- 2 – 6 s
How thick the liquid is. A thicker (more viscous) fluid drags far more at the wall, cutting the flow rate for the same push and pipe.
The flow rate depends on the FOURTH power of this radius — halving it cuts the flow to a sixteenth, everything else unchanged.
A longer pipe means more wall to drag against over the same pressure push, so the flow rate falls in direct proportion.
The pressure difference pushing fluid from one end of the pipe to the other. The flow rate rises in direct proportion to this.
How long the clip runs — long enough to watch the flat starting line bow out into the full parabolic velocity profile.