Chemin, Gallagher, and Paicu obtained in 2010 a class of large initial data that generate
a global smooth solution to the three-dimensional, incompressible Navier–Stokes
equation. The data varies slowly in the vertical direction — it is expressed as a function of
— and it has a norm that
blows up as the small parameter goes to zero. This type of initial data can be regarded as an
ill prepared
case, in contrast with the
well prepared case treated in earlier papers. The data was supposed to evolve in a
special domain, namely
.
The choice of a periodic domain in the horizontal variable played an important role.
The aim of this article is to study the case where the fluid evolves in the whole
space
.
In this case, we have to overcome the difficulties coming from very low horizontal
frequencies. We consider in this paper an intermediate situation between the well
prepared case and ill prepared situation (the norms of the horizontal components of
initial data are small but the norm of the vertical component blows up as the small
parameter goes to zero). The proof uses the analytical-type estimates and the special
structure of the nonlinear term of the equation.
Keywords
Navier–Stokes equations, global well-posedness, large data