ABSTRACT
The main purpose of this paper is to show that in a three-dimensional exterior Lipschitz domain the stationary Navier–Stokes equations have a solution which converges at infinity to a constant vector and assumes a boundary value
(or
if Ω is of class
), provided
. Moreover, for large value of the viscosity ν we prove existence, uniqueness and asymptotics of a solution
for Ω and a polar symmetric.
AMS CLASSIFICATIONS:
Disclosure statement
No potential conflict of interest was reported by the authors.
Notes
1 We use a standard notation as, e.g. in [Citation3]. In particular, italic light-face letters, except , denote scalars or vectors,
and
usually stands for points running on domains and surfaces, respectively;
is the origin of the reference frame
;
,
; n denotes the exterior (with respect to Ω) normal to
;
is the vector with components
.
is the ball of radius R centered at x;
;
(we suppose
);
;
. For
,
,
is the completion of
with respect to the norm
and
is the dual space of
; the subscript σ in
, where K is a functional space, means that the elements of K are divergence free. If
and
are functions defined in a neighborhood of the infinity, the Landau symbols
,
mean respectively that
and
is bounded at large distance.
2 On the contrary, starting from the paper by Giga [Citation33] the problem of existence of solutions to the Stokes and Navier–Stokes problems in bounded domains with data in has been extensively studied (see [Citation3] and the references therein).
3 Under suitable symmetry assumptions, the existence of solution to (Equation1(1)
(1) ) without any assumption on the boundary datum is proved in [Citation10]. An analogous problem in four dimensions has been recently studied in [Citation34].
4 See (i)–(vii) of Section 2.1.
5 The way in which the solution attains the boundary value will be clear from the context of the proof of Theorem 1.1.
6 It is worth recalling that uniqueness is lost for small viscosity (see, e.g. [Citation3]).
7 A trivial but large class of solutions to (Equation1(1)
(1) )
vanishing at infinity more rapidly than
or belonging to
are given by the pairs
with
harmonic functions in Ω. Clearly,
(and
is also a solution to the Stokes equations with constant pressure and must satisfy necessary compatibility conditions, for instance
, for every (large) R.
8 In such a case, (Equation16(16)
(16) )
has to be understood as the value of the functional
at
.
9 Note that this knowledge must be exact, not approximate!
10 In [Citation28], existence is proved for . The extension of this result to system (Equation79
(79)
(79) ) does not present difficulties.
11 We extend w to Ω by setting outside
.