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Re: FLOW?



On 05/12/2003 07:07 AM, David Abineri wrote:
FLOW is defined as the integral of F dot T ds where F is a velocity
field and T is the unit vector tangent to the path being taken.

Really? That's a new one on me.


My question is, from more of a Physics point of view, what are the units
of Flow typically? What is Flow really measuring?
I believe I need a way of thinking about what this definition is really
saying and what it is really calculating.

To me, "flow" means stuff crossing a boundary.
It's slightly ambiguous: it's either
-- total stuff crossing the total boundary, or
-- stuff crossing per unit area of boundary.

The units depend on what's flowing. If we are
talking about particles, then the units are
-- particles per second, or
-- particles per second per unit area.

Instead of particles it could be charge, mass,
energy, momentum, lepton number, entropy, or
any other more-or-less conserved quantity.

The idea of conservative flow is related to the
continuity of world-lines.

http://www.monmouth.com/~jsd/physics/conservative-flow.htm