Editing Froude number (section)

===Incompressible Navier–Stokes momentum equation===
{{see also|Navier–Stokes equations#Incompressible flow}}
Incompressible Navier–Stokes momentum equation is a Cauchy momentum equation with the [[Pascal law]] and [[Stokes' law|Stokes's law]] being the stress constitutive relations:
<math display="block">\boldsymbol \sigma = p \mathbf I + \mu \left(\nabla\mathbf{u} +  ( \nabla\mathbf{u} )^\mathsf{T}\right) </math>
in nondimensional convective form it is:{{sfn|Shih|2009|p=}}
<math display="block">\frac{D \mathbf u}{D t} + \mathrm{Eu} \frac {\nabla p}{\rho} = \frac 1 {\mathrm{Re}} \nabla^2 u + \frac 1 {\mathrm{Fr}^2} \hat g </math>
where {{math|Re}} is the [[Reynolds number]]. Free Navier–Stokes equations are [[dissipative system|dissipative]] (non conservative).