[engchess]

hiiii everyone ... i wish u can help me in this .. i have a mass transport project and it is about couette flow .. in the cylinder i have two fluid water and oil .. my dr. ask me a aquetstion to look after it he says why the water rotates around the oil why not the oppisite he give me a hint he says it is to minimize the energy but he want the princibple that states that ? .. can u help me do u have any idea about what principle he is talking about !

[Borek]

When water and oil separates - which one is at the bottom and why?

[engchess]

when they are seperates i do not know , but he wants why when they are rotating in the cylinder the oil centerized the water

[Borek]

Reason is the same, just forces different. Think it over.

[Donaldson Tan]

Compare their density. Which is "lighter"?

Where does the "lighter" component go?

[engchess]

yeah i said the density thing ,but he said that beside this there is another reason about minimizing their energy and he wants the name of the principle that says so ..

[eugenedakin]

Hi engchess,

There is a part of Canada which produces oil which has a higher density than water (Oil density = 1.09, salt-water density = 1.01).  In this case the oil would be at the bottom.  I believe that almost all refined or natural oils have a density near or below 1.0. 

If I said all oils have a density below 1.0, someone would know of a exception-to-the-rule.

 

Best of luck,

Eugene