If the dynamic μ and bulk ζ ζ viscosities are assumed to be uniform in space, the equations in convective form can be simplified further. By computing the divergence of the stress tensor, since the divergence of tensor ∇ ∇ u is ∇ ∇ 2 u and the divergence of tensor ( ∇ ∇ u ) T is ∇ ∇ ( ∇ ∇ ⋅ ⋅ u ) , one finally arrives to the compressible Navier–Stokes momentum equation: