Navier-Stokes equations

The incompressible Navier-Stokes equations are $\rho \left({\frac {\partial \mathbf {u} }{\partial t}}+\left(\mathbf {u} \cdot \nabla \right)\mathbf {u} \right)=-\nabla p+\mu \nabla ^{2}\mathbf {u} \,,$