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Equations
Flow field
Rate of production
Accumulation
Conserved quantity, internal energy
Nonconserved quantity, entropy
A flow field is a vector field
Discussion
Accumulation was demonstrated graphically in Mathematica animation in the previous lecture
Accumulation is the negative of the divergence of the flux plus the creation or destruction of material
Consider the accumulation of internal energy, a conserved quantity. It is equal to the negative of the divergence of internal energy.
Entropy change is due to net flux, and there is a production term.