释义 |
local derivative local derivative[′lō·kəl də′riv·əd·iv] (fluid mechanics) The rate of change of a quantity f with respect to time at a fixed point of a fluid, ∂ f /∂ t; it is related to the individual derivative df/dt through the expression ∂ f /∂ t = df/dt - V · ∇ f, where f is a thermodynamic property f (x,y,z,t) of the fluid, V the vector velocity of the fluid, and ∇ the del operator. |