This quantity is equal to the curl of the stream function.
The mass continuity equation states that the divergence of this quantity times the density is the negative of the time derivative of the density. This quantity is equal to the curl of the stream function. When its divergence is zero, the flow is incompressible, but when this quantity's curl is zero, irrotational flow results. Along with the characteristic length and the density, it is found in the numerator of the Reynolds number, and if its time derivative is zero, the flow is steady. The cross-sectional area times this quantity is the volumetric flow rate. For 10 points, name this quantity which represents how quickly particles in a fluid are moving, the time derivative of position.
The mass continuity equation states that the divergence of this quantity times the density is the negative of the time derivative of the density.
fluid velocity [accept flow velocity]