Pressure distribution in a vertical falling film with a free surface

[E***@hotmail.ca]

If you measure the pressure at two different heights, what would you get ?

a) P_top = P_bottom = Patm
b) P_bottom > P_top

[dlzc]

Post by E***@hotmail.ca
If you measure the pressure at two different heights,
what would you get ?
a) P_top = P_bottom = Patm

Correct, atmospheric pressure increases slightly with elevation.

Or are you looking for pressure through the film?

Post by E***@hotmail.ca
b) P_bottom > P_top

Also correct, but just because atmospheric pressure rises with decreases in altitude.

David A. Smith

[E***@hotmail.ca]

Yes im talking about the pressure inside the liquid film.
There is thus no hydrostatic pressure ?

[dlzc]

Dear EuhNg...:

On Wednesday, October 23, 2013 9:28:43 PM UTC-7, ***@hotmail.ca wrote:
...

Post by E***@hotmail.ca
Yes im talking about the pressure inside
the liquid film. There is thus no hydrostatic
pressure ?

Assuming it is falling straight down, then the fluid below is not supporting the fluid above it. If the "waterfall" is accelerating downwards, and is much, much wider than it is thick, then self-affinity will not be a very strong player until droplets start to form.

I may be wrong.

Try here:
http://books.google.im/books?id=5bCU198TUccC&pg=PA5&lpg=PA5&dq=hydrostatic+pressure+variations+falling+film&source=bl&ots=_DyQOlKMcT&sig=iwfgz4LQHAk5d2WtcWeI1D9GvJI&hl=en&sa=X&ei=CDtpUpLyBaqdyQGd74GICw&ved=0CDwQ6AEwBA#v=onepage&q=hydrostatic%20pressure%20variations%20falling%20film&f=false

David A. Smith