Fluid Dynamics
In fluid dynamics, the continuity equation states that, in any steady state process, the rate at which mass enters a system is equal to the rate at which mass leaves the system.
The differential form of the continuity equation is:
where
- ρ is fluid density,
- t is time,
- u is the flow velocity vector field.
If ρ is a constant, as in the case of incompressible flow, the mass continuity equation simplifies to a volume continuity equation:
which means that the divergence of velocity field is zero everywhere. Physically, this is equivalent to saying that the local volume dilation rate is zero.
Further, the Navier-Stokes equations form a vector continuity equation describing the conservation of linear momentum.
Read more about this topic: Continuity Equation
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