User:Mohitagg

We show that storage function's rate of change is equal to second order variation of the rate of entropy production

$$ \dot{W} = -\delta^2 \sigma_S $$

The rate of entropy production is a product of flux density $$ J $$ and potential gradient $$ X $$

$$ \sigma_S = JX $$

Now I think based on how the flux J is defined we have 2 cases:

1) J is a function of X e.g. Linear range of non-equilibirium thermodynamics where $$ J = LX $$.

2) J is independent of X e.g. forced convection where flow is proportional to pressure gradient and pressure is constant.