Laminar flow in pipe

[bitchingstrategy]

isn't that a burette? :O

[yanjnus]

Very cool video. What is the speed of the mediun fluid? Did you maintain the same flow speed for the red fluid in the pipe and the medium fluid outside the pipe? What will happen if the two speeds are different?

[trashbeck]

The flow enters the chamber from the right, it then enters the bellmouth, and reversing, goes down the tube leftwards. The ink is injected into it, and it exits on the right. If you look at Reynolds' 1883 paper, he does the same, but on a larger scale. Hope that is clear enough.

[yanjnus]

Thanks for clarification,

[jamaicanboye]

I saw your video on turbulent flow and it looked like you were using the same particles/liquid in both and the geometry of the tubes are identical. So, how are you controlling if it is laminar or turbulent flow? Are you simply changing the flow rate and if so did you increase or decrease it?

[trashbeck]

Increase the flow rate. If you are really clever (like me :-P) you can run two taps at the same rate, with the hot one turbulent (cloudy) and the cold one clear (laminar).

as Re is rho*v*d/mu, increasing? v or decreasing mu increases the turbulence.

[jamaicanboye]

The changing Reynolds number based on changes with v and mu make sense, but explain to me the theory based on the temperature. If hot turbulent and if cold laminar.

[trashbeck]

As the viscosity of a liquid roughly halves every 10 degrees (C) that the temperature rises, a 30 degree hotter water flow from an equivalent tap at the same flow rate has about 8 time the Reynolds number. So decrease the flow on a cold tap until it is just clear. Setting the same flow rate (time a cup filling) on the hot tap will produce a cloudy flow. Well it did for me.

[przemaz]

it should be called - almost laminar :)

[the0spastic0chicken]

as it becomes turbulent towards the end :) high five for the physics nerds!