Could You please help me with this phrase? It's a long phrase and I couldn't relate the begining to the end specially I can't understand what would mean "over which"? at least in this context.
In practice, the range of flow conditions, over which the entire liquid mass flow rate is contained as a symmetrical film on the channel wal with a smooth interface between the film and the vapour core, is very small indeed.
I also think the sentence is wrong. I'm not sure I understand "over which" here either.
The basic sentence is "The range of flow conditions is very small indeed." Which flow conditions? The flow conditions over which the entire mass flow rate is contained =
The flow conditions which the entire mass flow rate is contained over.
So, the author is asserting that the mass flow rate is contained over certain flow conditions. To me, this is meaningless.
I think it means "for which", and "flow rate" should be "flow" because the flow rate can't be described as a symmetrical film, but the flow can. Maybe "contained" should be "constrained"?
"The range of conditions for which the flow is constrained as described is very small." "There is only a small range of flow conditions that constrain the flow as described - ie. as a symmetrical film on the channel wall with a smooth interface between the film and the vapour core.
But perhaps technically it's possible to use "over which" with 'conditions'. "X occurs in conditions over which Y applies". I don't know. It still means "for which".