The divergence of this quantity times density plus the time derivative of density (*) equals zero according to one of Euler's equations, and Bernoulli's equation is quadratic in this quantity.
The square of this quantity multiplied by density times the Fanning friction factor over two equals the shear stress at the wall of a pipe. Multiplying the square of this quantity by density over the bulk modulus gives the Cauchy number. The divergence of this quantity times density plus the time derivative of density (*) equals zero according to one of Euler's equations, and Bernoulli's equation is quadratic in this quantity. If the divergence of this quantity is zero, the flow is incompressible. In a horizontal pipe, an increase in this quantity will be accompanied by a decrease in pressure. Taking the curl of this quantity gives the vorticity. For 10 points, give this quantity that expresses the rate at which a fluid flows.
The square of this quantity multiplied by density times the Fanning friction factor over two equals the shear stress at the wall of a pipe.
fluid velocity (or flow velocity; or velocity field; prompt on "u"or "v")