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Re: advection

At 10:45 AM 6/12/01 -0400, Carl E. Mungan wrote:

"Advection" - haven't heard that word in so long I've forgotten it.
What is the difference between "advection" and "convection" in their
technical meanings? Even after consulting a dictionary I can't tell:
both seem to mean a change in the properties of a fluid due to
large-scale mixing. Even the Latin doesn't help me: "advection" means
"to carry to," while "convection" means "to carry together."

I think the Latin does tell the story.

Convection is a more vague and general term. Loosely, compare
-- Advection: to carry to
-- Convection: to carry to and fro

Example: The convection of air in a closed room
Example: Rayleigh-Bénard convection.

Advection is a more specialized term. I use it in cases where the transport _to_ the place of interest is significant, but the return current is either uninteresting or will be accounted for separately.
Example: advection fog
Example: advection of energy, entropy, and chemical species in a continuous-flow chemical reactor